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THE 


DUBLIN  DISSECTOR 


OR 

MANUAL  OF  ANATOMY  s 


COMPRISING 


t \ 


A CONCISE  DESCRIPTION 


THE  BONES,  MUSCLES,  VESSELS,  NERVES  AND  VISCERA, 


THE  RELATIVE  ANATOMY  OF  THE  DIFFERENT  REGIONS 


OF  THE  HUMAN  BODY* 


FOR  THE 

Slse  of  Stunents  fit  tjje  Ufssecttng  3£loom. 


BY  A MEMBER 

OF  THE  ROYAL  COLLEGE  OF  5URGEONS  IN  IRELAND; 
FIRST  AMERICAN  FROM  THE  SECOND  DUBLIN  EDITION, 


WASHINGTON: 

STEREOTYPED  AND  PUBLISHED  BY  DUFF  GREEN= 

1835. 


t> 


CONTENTS. 


V 


Thoracic  ganglions  - 

•Page 

- 203 

Dissection  of  the  joints 

Page 

237 

Splanchnic  nerves 

- 

- 203 

' Ligaments  of  the  lower  jaw 

237 

Solar  plexus 

- 

- '203 

Ligaments  of  the  occiput 

238 

Organs  of  sense 

- 

- 204 

Ligaments  of  the  vertebrae 

239 

Nose 

- 

- 204 

Ligaments  of  the  ribs 

- 

239 

Taste 

■ - 

- 206 

Ligaments  of  the  pelvis 

- 

240 

Ear 

- 

■ 2 06 

Ligaments  of  the  clavicle 

- 

240 

Eye 

- 

- 209 

Ligaments  of  the  shoulder  joint 

- 

241 

Muscles  of  the  orbit 

• - 

- 209 

Ligaments  of  the  elbow 

- 

24? 

Lachrymal  apparatus 

- 

- 209 

Ligaments  of  the  wrist 

- 

243 

Eyelids 

- 

- 210 

Ligaments  of  the  hip  joint 

- 

244 

Globe  of  the  eye 

- 

- 211 

Ligaments  of  the  knee  joint 

- 

244 

Skin 

- 

- 215 

Ligaments  of  the  ankle 

- 

246 

Arterial  system 

- 

217 

Description  of  the  bones 

- 

247 

Aorta 

- 

- 217 

Vertebrae 

- 

248 

Coronary  arteries 

» 

- 217 

Sternum 

- 

252 

Arteria  innominata 

*> 

- 218 

Ribs 

- 

252 

Carotid  arteries 

- 

- 218 

Thorax 

- 

253 

External  carotid 

- 

- 218 

Sacrum 

- 

254 

Internal  maxillary  artery 

* 

- 219 

Ossa  innominata 

- 

255 

Internal  carotid 

- 220 

Ilium 

- 

255 

Opthalmic  artery 

- 

- 220 

Ischium 

- 

256 

Subclavian  arteries 

- 

. 221 

Pubis 

- 

257 

Brachial  artery 

- 

- 223 

Acetabulum 

- 

2 57 

Ulnar  artery 

- 

- 224 

Pelvis 

- 

257 

Radial  artery 

- 

- 225 

Head 

- 

259 

Thoracic  aorta 

- 

- 225 

Frontal  bone 

- 

259 

Abdominal  aorta 

- 

- 226 

Parietal 

- 

261 

Coeliac  axis 

- 

- 226 

Occipital 

262 

Mesenteric  arteries 

- 227 

Temporal 

- 

263 

Iliac  arteries 

- 

- 228 

Ethmoid 

O 

265 

Internal  iliac 

- 

- 228 

Sphenoid 

- 

266 

External  iliac 

- 

- 229 

Sutures 

- 

268 

Femoral  artery 

- 

- 229 

Skull  in  general 

- 

269 

Poplitxal  artery 

- 

- 230 

Bones  of  the  face 

- 

270 

Anterior  tibial  artery 

- 

- 231 

Malar  bone 

- 

270 

Posterior  tibial 

- 

- 231 

Superior  maxillary 

- 

270 

Peronal  artery 

- 

- 231 

Palate  bone 

- 

272 

Venous  system 

- 

- 232 

Inferior  spongy  bone 

- 

273 

External  jugular  vein 

- 

- 232 

Lachrymal  bone 

- 

273 

Internal  jugular  vein 

- 

- 232 

Nasal  bone 

- 

273 

Veins  of  the  arm 

- 

- 232 

Vomer 

- 

273 

Vena  cava  superior 

- 

- 233 

Inferior  maxillary  bone 

O 

274 

Veins  of  the  leg 

- 

- 233- 

Teeth 

- 

275 

Inferior  vena  cava 

- 

- 233 

Orbit 

- 

275 

Vena  portce 

- 

- 234 

Palatine  region 

. 

276 

Lymphatic  vessels 

- 

- 234 

Temporal  fossa 

- 

276 

Thoracic  duct 

- 

- 235 

Zygomatic  fossa 

- 

276 

Foetal  circulation 

. 235 

Pterygo  maxillary  fossa 

- 

276 

Thymus  gland 

- 236 

Femur  ... 

- 

276 

CONTENTS  OF  APPENDIX. 


Directions  for  opening  the  head 

the  thorax 

the  abdomen  - 

Morbid  appearances  in  the  brain  - 

in  the  thorax  - 

in  the  abdomen 

in  the  kidney  - 

— - in  the  bladder 


Morbid  appearances  in  the  uterus  - 

Laennec’s  division  of  the  thorax  into 
.fifteen  regions 

A concise  view  of  the  ligaments  and 
muscles  concerned  in  simple  dislo- 
cations .... 

Directions  for  making  vascular,  prepa- 
rations .... 


292 

292 

292 

293 

294 
296 

298 

299 


300 

301 

302 

311 


I 


' 

- 

. 


. 


' 


■ 

. 


. 


1"  , v 

. 

- 

\ " 

■ ■ 
\ 

* 


CONTENTS 


External  parts  of 
Occipito-frontalis 
External  muscles  of  the  ear 
Face  .... 

Orbicularis  palpebrarum 
Tensor  tarsi 

Muscles  of  the  nose,  lips,  &c. 

Buccinator  muscle 
Parotid  gland 

Masseter,  temporal,  and  pterygoid 
muscles  - 

Vessels  and  nerves  of  the  face 
Neck  .... 

Platisma  myoides  and  cervical  fascia 
Sterno-cleido  mastoid  muscle 
Division  of  the  neck  into  triangular 
regions 

Sterno-hyoid,  thyroid,  and  omo-hyoid 
muscles  ... 

Thyroid  gland 
Digastric  muscle 
Submaxillary  gland 
Mylo-hyoid  and  genio-hyoid  muscles 
Sublingual  gland 
Hyo  and  genio  hyo  glossi  muscles 
Styloid  muscles 
Vessels  and  nerves  of  the  neck 
Mouth  .... 

Tongue  .... 
Pharynx,  constrictors  of ; openings  in 
Palate,  arches  of ; uvula 
Levator  palati,  tensor  palati,  palato- 
glossus, &c.  &c. 

(Esophagus 

Larynx  ; cartilages,  muscles,  &c.  Sec. 

Deep  muscles  of  the  neck  ; longus  colli, 
Muscles  on  the  fore-part  of  the  thorax 
Pectoralis  major,  &c.  &c, 

Serratus  magnus 
Intercostal  muscles 
Levatores  costarum,  triangularis  sterni 
Axilla  .... 

Thorax  .... 
Anterior  mediastinum 
Pleurae  .... 
Posterior  mediastinum,  vena  azygos, 
thoracic  duct,  &c.  &c.  - * 38 


Tage 


Lungs  - - - - 40 

Pericardium  - - - 41 

Heart  - - - - 42 

Pulmonary  artery  - - 44 

Aorta  - - • 45 

Parts  passing  through  the  upper  ori- 
fice of  the  thorax  - - 46 

Trachea  - - - 47 

Muscles  of  the  back  ; lumbar  fascia  48 
Trapezius  - - - 49 

Latissimus  dorsi  - - - 49 

Rhomboid,  levator  anguli  scapula:  - 50 

Recti  and  obliqui  capitis  postici  - 54 

Upper  extremity  - - 55 

Fascia  and  superficial  veins  of  the  arm  55 
Deltoid  muscle  - - -56 

Supra  and  infra-spinatus,  and  teres 
minor  muscles  - - 56 

Subscapular  muscle,  capsular  muscles  57 
Biceps  muscle  - - - 59 

Triceps  muscle  - - - 60 

Vessels  of  the  arm,  brachial  artery  - 61 

Brachial  plexus  of  nerves  - 62 

Forearm  and  hand  • - 62 

Cutaneous  veins,  basilic,  cephalic,  8cc.  62 
Fascia  of  the  forearm  and  hand  - 63 

Palmaris  brevis  muscle  - - 63 

Pronator  and  flexor  muscles,  superfi. 

cial  and  deep  - - - 64 

Supinator  and  extensor  muscles,  su- 
perficial and  deep  - . 66 

Muscles  in  the  hand  - - 69 

Vessels  of  the  forearm  and  hand,  radial 
and  ulnar  arteries  - - 72 

Nerves  of  do.  - - - 73 

Abdomen  - - - - 73 

Superficial  fascia  - - - 73 

Obliquus  externus  - - - 74 

Linea  alba,  linea  semilunaris  - - 75 

External  inguinal  ring  - 76 

Poupart’s  ligament  - - 76 

Obliquus  internus  - - - 77 

Cremaster  - - - 78 

Transversalis  muscle  - - 79 

Fascia  transversalis  - - 80 

Internal  abdominal  ring  - - 80 

Spermatic  or  inguinal  canal  - - 81 

iii 


Page 

the  HEAD  - 1 

1 

2 


4 

4 

6 

6 

7 

10 

11 

12 

13 

14 

14 

15 

16 
16 
17 

17 

18 
18 
19 
22 
22 
23 
25 


26 

27 

27 

30 

32 

32 

34 

34 

35 

35 

36 

36 

37 


IV 


CONTENTS 


OBLIQUE  INOTTINAL  HERNIA 

Direct  or  ventro-inguinal  hernia 
Femoral  or  crural  hernia 
Inguinal  glands 
Saphena  vein 
Fascia  lata  ' 

Fascia  iliaca 
Femoral  or  crural  ring 
Fascia  propria 
Regions  of  the  abdomen 
Peritonaeum  - 

Omenta,  mesocolons,  &c.  &.c. 

Stomach 

Duodenum,  jejunum,  ilium 

Large  intestine,  ceecum,  ilio-colic  valve 

Structure  of  the  intestinal  canal 

Liver  .... 

Gall-bladder 

Spleen  - 

Pancreas  .... 
Vessels  and  nerves  of  the  abdomen 
Kidney  .... 
Ureter  .... 

Bladder  .... 
Urethra  .... 
Diaphragm  ■ 

Quadratus  lumborum,  psos  and  iliacus 
muscles 

Perinseum  in  the  male 
Sphincter  ani ; superficial  fascia 
Compressor  penis,  accelerator  urinac 
Triangular  ligament  of  the  urethra  - 
Cowper’s  glands  ... 
Levator  ani  .... 
Surgical  anatomy  of  the  parts  con- 
cerned in  lithotomy 
Pubic  ligament 
Neck  of  the  bladder  - 
Pelvic  viscera,  peritonamm  - 
Urinary  bladder 

Pelvic,  vesical,  and  obturator  fascia:  - 

Ligaments  of  the  bladder 

Coats  of  the  bladder  - 

Organs  of  generation  in  the  male 

Scrotum 

Tunica  vaginalis,  albuginea,  Sic. 
Testicle  - ' - 

Vas  deferens.  Spermatic  cord 
Vesicu'ls  seminales 
Prostate  gland 

Penis  .... 

Urethra  .... 

Method  of  injecting  the  perns  and  cor- 
pus spongiosium  urethra 
Female  organs  of  generation  ■ 

Uterus,  &c.  &c.  &c. 

Inferior  extremities  - 
Fascia  lata 

Muscles  on  the  forepart  and  sides  of 
the  thigh  - 


Page 

Triceps  adductor  muscle  - - 137 

Femoral  artery ; anterior  crural  nerve  138 

Dissection  of  the  posterior  part  of  the 
thigh  - - - -139 

Gluteus maximus, medius, &c.  &.c.  &c.  140 

Obturator  internus,  externus,  &c.  - 142 

Glutseal  sciatic  vessels  lie.  - 143 

Sciatic  nerve,  &c.  - - - 144 

Hamstring  muscles  - - - 145 

Popliteal  space  - - - 146 

Leg ; fascia,  subcutaneous  veins  - 147 

Plantar  fascia  - - - 148 

Muscles  on  the  forepart  of  the  leg,  tibi- 
alis anticus,  &c.  - - 149 

Anterior  tibial  vessels  and  nerves  - 151 

Muscles  on  the  back  of  the  leg,  super- 
ficial and  deep  - - - 1 52 

Muscles  of  the  foot  - - - I55 

Posterior  tibial  vessels  and  nerves  - 150 

Brain  ....  160 

Dura  mater  - - - - 160 

Sinuses  - - - - 162 

Arachnoid  membrane,  kc.  - - 1 64 

Cerebrum  - - - . 165 

Ventricles  ....  168 

Cerebellum  - - - - 172 

Medulla  oblongata  - - - 1 73 

Origin  of  the  cerebral  nerves  173 

Medulla  spinalis  - - - 176 

Dissection  of  the  brain  from  below  178 
Vessels  of  the  brain  - - 180 

Cerebral  nerves,  olfactory  - - 1S1 

Optic  nerves  - - - 181 

Third  and  fourth  - - - 182 

Opthalmic  nerve  - - - 183 

Opthalmic  ganglion  - 184 

Superior  maxillary  nerve  - - 184 

Meckel’s  ganglion  - - - 1S4 

Vidian  nerve,  corda  tvmpani,  sub  max- 
illary ganglion  - - - 1S5 

Facial  nerve  - - - 188 

Auditory  nerve  - - - 188 

Glosso-pharyngeal  nerve  - - 189 

Pneumo-gastric  nerve  - - 189 

Pharyngeal  plexus  - - - 190 

Laryngeal  nerves  - - - 190 

Pulmonary  plexus  • - - 191 

Lingual  nerve  - - - 191 

Spinal  nerves  - - - 192 

Cervical  plexus  - - - 192 

Phrenic  nerve  - - - 192 

Brachial  plexus  - - - 193 

Nerves  of  the  arm  - - - 194 

Dorsal  nerves  - - - 196 

Lumbar  nerves,  and  plexus  - - 196 

Sacral  nerves  and  plexus  - 198 

Sciatic  nerve  ...  198 

Sympathetic  nerve  and  the  cervical 
.ganglions  ...  200 

Cardiac  nerves  - - 202 


Page 

81 

82 

82 

83 

83 

83 

84 

85 

85 

87 

88 

90 

92 

94 

95 

96 

98 

100 

101 

101 

102 

104 

106 

118 

127 

107 

109 

110 

111 

112 

114 

114 

114 

116 

116 

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117 

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119 

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122 

122 

122 

123 

124 

125 

125 

126 

127 

128 

130 

131 

132 

132 

134 


THE 


DUBLIN  DISSECTOR. 


CHAPTER  I. 

I 

DISSECTION  OF  THE  EXTERNAL  PARTS  OF  THE  HEAD  AND  FACE. 

§ 1. — External  Parts  of  the  Head. 

The  integuments  covering  the  cranium  are  firm  and  dense,  although  when 
felt  they  give  the  sensation  of  being  thin  : the  cuticle  is  delicate,  but  the  cutis 
is  very  thick ; the  subjacent  cellular  membrane  contains  granulated  fat,  and 
the  bulbs  of  the  hairs,  which  afterwards  perforate  the  skin  in  an  oblique  di- 
rection. The  cellular  tissue  here  has  partly  a ligamentous  structure,  and 
adheres  so  intimately  to  the  subjacent  muscular  and  tendinous  expansion, 
that  the  inexperienced  student  may  find  some  difficulty  in  exposing  the 
surface  of  the  latter.  Make  an  incision  through  the  integuments  along  the 
median  line,  from  the  tuberosity  of  the  occipital  bone,  as  far  forwards  as  the 
lower  part  of  the  forehead : from  each  extremity  of  this,  make  a transverse 
incision  about  three  inches  long  ; let  the  posterior  one  be  parallel  to  the  su- 
perior transverse  ridge  of  the  occipital  bone,  and  the  anterior  one  parallel, 
and  about  half  an  inch  superior  to  the  eyebrow;  cautiously  dissect  off  the 
integuments  from  the  subjacent  muscular  and  tendinous  expansion,  which  is 
the  occipito-frontalis.  This  muscle,  like  most  of  the  superficial  muscles  of 
the  face,  is  closely  attached  to  the  skin,  which  circumstance,  added  to  the 
paleness  and  smallness  of  their  fibres,  renders  their  dissection  somewhat  dif- 
ficult and  tedious.  Most  of  the  superficial  muscles  of  the  head  and  face, 
during  life,  assist  some  of  the  organs  of  sense,  and  contribute  to  produce 
certain  changes  in  the  countenance,  indicative  of  character  or  passion. 

The  superficial  muscles  of  the  head  are  divided  into  those  of  the  cranium 
and  face.  Those  of  the  cranium  are  the  occipito-frontalis,  and  the  three 
common  muscles  of  the  ear. 

Occipito-Frontalis  is  the  only  muscle  which  properly  belongs  to  the  scalp  ; 
it  is  thin  and  broad,  fleshy  at  each  extremity,  aponeurotic  in  the  centre.  It 
arises  by  tendinous  and  fleshy  fibres  on  each  side  of  the  middle  line,  from 
the  two  external  thirds  of  the  superior  transverse  ridge  of  the  occipital  bone, 
and  from  the  external  and  posterior  part  of  the  mastoid  process  ; the  fibres 
on  each  side  ascend,  from  behind  forwards,  and  from  without  inwards,  and 
soon  terminate  in  one  thin  and  broad  tendon,  which  extends  over  the  upper 
and  lateral  parts  of  the  cranium.— This  cranial  aponeurosis  having  arrived 
1 


2 


THE  DUBLIN  DISSECTOR, 


opposite  the  coronal  suture,  ends  in  two  fleshy  portions,  broader  and  thicker 
than  the  posterior  extremities  of  this  muscle  ; these  anterior  portions,  which 
are  thicker  externally  than  internally,  descend  over  the  frontal  bone,  and  are 
inserted,  fleshy  on  each  side,  into  the  integument  of  the  eyebrow,  mixing  with 
the  fibres  of  the  corrugator-supercilii  and  orbicularis  palpebrarum  muscles  ; 
a small  fleshy  slip  is  often  continued  down  along  the  nasal  bones,  and  is  at- 
tached to  the  angular  process  of  the  os  frontis,  and  inferiorly  to  the  nasal 
bones  or  cartilages  : this  slip  is  described  by  some  as  a distinct  muscle,  under 
the  name  of  pyramidalis  nasi,  or  fronto-nasalis. — Use.  The  occipito-fron- 
talis  muscle  can  raise  the  eyebrows  and  integument  of  the  forehead  into 
transverse  wrinkles,  draw  the  eyebrows  a little  outwards,  am!  make  tense  the 
skin  of  the  upper  eyelids  ; also  pull  the  scalp  backwards;  but  if  the  eye- 
brows be  depressed  and  fixed,  this  muscle  can  then  (particularly  in  some 
persons),  draw  the  scalp  downwards  and  forwards.  This  muscle  is  very 
closely  connected  to  the  scalp,  particularly  in  front,  but  loosely  to  the  cranium, 
it  can  thus  move  easily  on  the  latter,  carrying  with  it  the  former.  Its  origin 
is  connected  with  the  sterno-mastoid,  trapezius  and  splenius  muscles,  and  its 
insertion  with  those  of  the  eyebrows.  Some  describe  the  occipito-frontalis, 
not  as  one,  but  as  four  distinct  muscles,  two  on  each  side,  under  the  names 
of  the  occipital  and  frontal  muscles  of  each  side,  and  consider  the  cranial 
aponeurosis  as  their  common  insertion.  Several  vessels  and  nerves  perforate 
this  muscle,  and  ramify  on  its  surface  and  in  the  integument,  viz.  anteriorly, 
the  supraorbital  branches  of  the  ophthalmic  nerve  and  artery ; laterally,  the 
temporal  and  posterior  auris  arteries  with  branches  of  the  portio  dura  and 
inferior  maxillary  nerves,  and  posteriorly,  the  occipital  arteries  spread  their 
branches  upwards  and  forwards,  accompanied  by  the  occipital  nerves,  branches 
of  the  cervical  plexus : the  integuments  in  this  region  are  thus  abundantly 
supplied  with  vessels  and  nerves  from  different  sources,  a circumstance  not 
only  of  anatomical  but  of  practical  importance. 

The  common  muscles  of  the  ear  are  three  in  number,  viz.  superior,  anterior, 
and  posterior  auris: 

Superior  Auris,  or  Attollens  Aurem,  is  a small,  thin,  triangular  muscle, 
arising  tendinous  from  the  cranial  aponeurosis  on  the  side  of  the  cranium, 
just  above  the  external  ear ; the  fibres  descend  converging,  become  fleshy, 
and  are  inserted  into  the  upper  and  anterior  part  of  the  cartilage  of  the  ear; 
— use,  to  raise  the  cartilage,  and  deepen  its  cavity.  This  muscle  is  between 
the  skin  and  temporal  fascia. 

Anterior  Auris,  or  Attrahens  Aurem,  is  connected  with  the  last,  is  small, 
and  often  indistinct;  it  arises  from  the  posterior  part  of  the  zygomatic  pro- 
cess, and  from  the  cranial  aponeurosis,  passes  backwards  and  downwards, 
and  is  inserted  into  the  anterior  part  of  the  helix;  use,  to  draw  the  external 
ear  forwards  and  upwards.  This  muscle  is  superficial,  and  lies  on  the  tem- 
poral fascia,  vessels  and  nerves. 

Posterior  Auris,  or  Retrahens  Aurem,  often  consists  of  two  or  three 
distinct  fasciculi,  it  is  the  strongest  of  these  auricular  muscles;  it  arises 
irom  the  mastoid  process  above  the  sterno-mastoid  muscle,  passes  forwards, 
and  is  inserted  into  the  back  part  of  the  concha.  This  muscle  is  covered 
only  by  the  skin,  and  lies  on  the  temporal  bone. 

In  addition  to  these  muscles,  which  move  the  external  ear,  there  are  several 


OR  MANUAL  OF  ANATOMY. 


3 


small  muscles  attached  to  different  parts  of  the  cartilages,  which  serve  to 
alter  their  form,  and  expand  their  cavities;  these  muscles,  as  also  those  in 
the  tympanum,  shall  be  described  hereafter  in  the  dissection  of  the  organ  of 
hearing.* 


§ 2. — Dissection  of  the  External  Parts  of  the  Face. 

The  muscles  of  the  face  require  careful  dissection  : they  are  delicate,  and 
often  very  pale ; they  may  be  classed  into  the  superficial  and  deep  : the 
former  into  those  of  the  eyelids,  nose,  mouth,  and  lips  ; the  latter  into  those 
of  the  lower  jaw  and  palate.  Make  an  incision  around  the  base  of  the  orbit, 
through  the  skin,  which  is  here  very  fine,  and  closely  adhering  to  the  fibres  of 
the  orbicularis  muscle  ; next  make  a perpendicular  incision  along  the  middle 
line  of  the  nose,  to  the  centre  of  the  upper  lip,  continue  this  in  a semicircular 
manner  round  the  angle  of  the  mouth  to  the  middle  of  the  lower  lip,  and 
thence  to  the  chin,  and  lastly  from  the  chin  to  the  angle  of  the  jaw;  reflect 
the  integuments  cautiously  from  the  eyelids  and  side  of  the  face,  as  far  back 
as  the  ear,  avoiding  the  slender  muscular  fibres  which  adhere  to  the  skin,  and 
the  vessels  and  nerves  which  will  be  exposed  in  this  dissection. 

Orbicularis  Palpebrarum,  broad  and  thin,  somewhat  oval,  in  some  sub- 
jects very  pale  and  indistinct,  in  others  strong  and  well  marked,  arises  by 
several  fleshy  fibres  from  the  internal  angular  process  of  the  os  frontis,  and 
from  the  upper  edge  of  a small  horizontal  tendon,  (which  tendon  is  about  one 
quarter  of  an  inch  in  length  ; it  is  inserted  internally  into  the  upper  edge 
of  the  nasal  process  of  the  superior  maxillary  bone,  thence  it  passes  outwards 
and  backwards  as  far  as  the  caruncula  lachrymalis,  and  divides  into  two  slips, 
which  are  inserted  into  the  tarsal  cartilages,  and  the  lachrymal  ducts;)  the 
fleshy  fibres  then  proceed  in  curves,  upwards  and  outwards,  along  the  upper 
edge  of  the  orbit,  the  eyelid,  and  tarsal  cartilage,  as  far  as  the  temple  and  ex- 
ternal commissure  of  the  eyelids  ; thence  the  fibres  curve  in  a similar  manner 
along  the  inferior  eyelid  and  edge  of  the  orbit  to  the  internal  can  thus,  where 
the  fibres  are  inserted  into  the  nasal  process  of  the  superior  maxilla,  and  into 
the  inferior  edge  of  the  horizontal  tendon. — Use,  to  close  the  eyelids,  chiefly 
by  depressing  the  superior;  to -press  the  tears  inwards  towards  thepuncta  lach- 
rymalia ; the  superior  and  external  fibres  can  also  depress  the  eyebrow,  and  thus 
oppose  the  occipito  frontalis;  the  inferior  fibres  can  raise  the  cheek,  draw  the 
lower  eyelid  inwards,  and  compress  the  lachrymal  sac  which  they  cover. 
This  muscle  is  covered  by  and  adheres  to  the  skin  ; superiorly  it  intermixes 
with  the  occipito-frontalis,  and  covers  the  corrugator  supercilii,  the  frontal 
vessels  and  nerves,  the  tarsal  cartilage,  and  levator  palpebrae  superioris  ; in- 
feriorly  it  intermixes  with  the  muscles  of  the  cheek  and  lips,  and  sometimes 
with  the  platisma  myoides,  and  covers  the  inferior  eyelid,  the  origin  of  the 
levator  anguli  oris  and  the  infra-orbital  vessels  and  nerves.  The  external  or 
orbital  fibres  of  this  muscle  are  strong  and  red,  and  run  circularly  round  the 
base  of  the  orbit;  the  middle  or  palpebral  fibres  are  pale,  thin,  and  scattered, 

* Previous  to,  or  immediately  after  dissecting-  the  muscles  of  the  face,  the  student 
should  examine  the  brain,  the  description  of  which  organ  will  be  found  at  the  head  of 
that  of  the  nervous  system. 


4 


THE  DUBLIN  DISSECTOR, 


and  are  contained  in  the  eyelids  ; the  internal  or  ciliary  portion  is  a thick 
but  pale  fasciculus,  situated  under  the  ciliae,  at  the  edge  of  each  eyelid. 
The  palbebral  and  ciliary  portion  adhere  more  closely  to  the  skin,  and  pre- 
sent an  elliptical  appearance,  as  the  fibres,  from  the  upper  and  lower  eyelid, 
intersect  each  other  at  the  outer  canthus,  and  adhere  to  the  ligament  of  the 
external  commissure.  The  horizontal  tendon  of  this  muscle  ( tendo  palpe- 
brarum or  tendo  oculi ) passes  across  the  lachrymal  sac  a little  above  its 
centre,  and  a strong  aponeurosis,  derived  from  its  upper  and  lower  edge, 
covers  all  the  anterior  surface  of  the  sac,  and  adheres  to  the  margins  of  the 
bony  gutter,  in  which  it  is  lodged.  This  tendon  can  be  seen  or  felt  through 
the  integuments  during  life,  particularly  when  the  muscle  is  in  action,  or 
when  the  eyelids  are  drawn  towards  the  temple.  In  the  operation  of  open- 
ing the  lachrymal  sac,  the  incision  should  commence  immediately  belowr  this 
tendon,  and  be  carried  obliquely  downwards  and  outwards,  to  the  extent  of 
about  half  an  inch.  Separate  the  orbicularis  from  the  occipito-frontalis  over 
the  internal  half  of  the  superciliary  arch,  the  tensor  tarsi  and  the  corrugatar 
supercilii  will  be  exposed. 

Tensor  Tarsi,  arises  tendinous  from  the  posterior  edge  of  the  os  unguis, 
passes  forwards,  divides  into  two  portions,  which  are  inserted  into  the  lach- 
rymal ducts,  along  which  the  fibres  extend  nearly  as  far  as  the  puncta : use  to 
draw  the  puncta  and  eyelids  into  close  contact  with  the  eye,  also  to  press  the 
puncta  towards  the  nose,  to  compress  the  lachrymal  sac,  and  to  force  out  the 
secretion  from  the  follicles  of  the  caruncula  lacrymalis. 

Corrugator  Supercilii,  arises  fleshy  from  the  internal  angular  process  of 
the  os  frontis,  passes  upwards  and  outwards,  and  is  inserted  into  the  middle 
of  the  eyebrow,  mixing  with  the  orbicularis  and  occipito-frontalis  muscles  ; 
use,  to  depress  and  approximate  the  eyebrows,  throwing  the  skin  of  the  fore- 
head into  vertical  wrinkles  : this  pair  of  muscles  cannot  act  separately;  thev 
directly  oppose  the  occipito  frontalis.  They  are  covered  by  the  orbicularis 
and  occipito-frontalis,  and  lie  on  the  os  frontis  and  on  the  frontal  nerve  and 
vessels. 

Pyramidalis  Nasi,  long,  thin,  often  wanting,  arises  from  the  occipito-fron- 
talis, decends  close  to  its  fellow,  along  the  nasal  bones,  becomes  broad  and 
aponeurotic,  and  is  inserted  into  the  compressor  nasi  muscle.  Use,  it  raises 
the  skin  covering  the  ossa  nasi. 

Compressor  Nasi,  is  thin  and  triangular,  placed  on  the  side  of  the  nose;  it 
arises  from  the  canine  fossa  in  the  superior  maxilla  : the  fibres  pass  forwards, 
expanding  over  the  ala  nasi,  and  are  inserted  by  a thin  aponeurosis  into  the 
dorsum  of  the  nose,  joining  some  fibres  from  the  opposite  side;  use,  to  press 
the  ala  toward  the  septum,  or  to  draw  it  from  it,  so  that  it  may  alternately 
enlarge  or  diminish  the  anterior  nares.  The  insertion  of  this  muscle  is  con- 
nected with  the  occipito-frontalis,  and  its  origin  with  the  following  muscle. 

Levator  Labii  Superioris,  Aljeque  Nasi,  is  long  and  thin,  placed  on  the 
side  of  the  nose,  between  the  orbit  and  the  upper  lip ; it  arises  by  two  origins, 
1.  from  the  upper  extremity  of  the  nasal  process  of  the  superior  maxilla ; 2. 
broad,  from  the  edge  of  the  orbit,  above  the  infra  orbital  hole;  the  fibres  de- 
scend and  converge  a little,  and  are  inserted  into  the  ala  nasi,  and  into  the 
upper  lip  aad  orbicularis  oris  muscle:  its  name  denotes  its  use.  The  external 
or  orbital  origin  of  this  muscle  is  covered  bv  the  orbicularis  palpebrarum  ; the 


OR  MANUAL  OF  ANATOMY. 


5 


angular  vein  and  artery  separate  its  origins  ; the  orbital  head  covers  the  infra- 
orbital nerve  and  vessels  and  the  levator  anguli  oris  muscle. 

Zygomaticus  Minor  is  very  small,  and  sometimes  wanting  ; it  arises  from 
the  upper  part  of  the  malar  bone,  passes  downwards  and  forwards,  and  is  in- 
serted into  the  upper  lip  near  the  commissure,  uniting  with  the  other  muscles 
which  are  inserted  there;  use,  to  draw  the  angle  of  the  mouth  upwards  and 
outwards,  as  in  smiling. 

Zygomaticus  Major,  is  long  and  narrow,  and  inferior  to  the  last ; arises 
tendinous  and  fleshy  from  the  lower  part  of  the  malar  bone,  near  the  zygomatic 
suture  : it  descends  obliquely  forward,  and  is  inserted  into  the  angle  of  the 
mouth. — Use,  to  draw  the  corner  of  the  mouth  upwards  and  backwards.  The 
zygomatic  muscles  are  partly  concealed  at  their  origin  by  the  orbicularis  pal- 
pebrarum; their  insertion  intermingles  with  the  levator,  depressor  anguli  and 
orbicularis  oris  muscles  ; they  lie  on  the  malar  bone,  and  cross  the  masseter 
and  buccinator  muscles;  they  are  imbedded  in  much  soft  adipose  substance. 

Levator  Anguli  Oris,  is' situated  about  the  middle  of  the  face,  behind  the 
orbital  portion  of  the  levator  labii  superioris  alaeque  nasi ; arises  from  the  ca- 
nine fossa  below  the  infra-orbital  foramen,  and  above  the  alveolus  of  the  first 
molar  tooth;  it  descends  obliquely  forward,  and  is  inserted  narrow  into  the 
commissure  of  the  lips,  and  into  the  orbicularis  oris;  its  name  denotes  its  use. 
This  muscle  is  covered  by  the  orbicularis  palpebrarum,  levator  labii  superioris 
alaeque  nasi,  and  by  the  zygomatic  muscles,  also  by  the  infraorbital  nerve  and 
vessels,  and  by  a quantity  of  soft  adeps;  it  lies  on  the  superior  maxilla  and 
on  the  mucous  membrane  of  the  mouth. 

Depressor  labii  superioris  Alaeque  Nasi,  a small  flat  muscle,  exposed  by 
everting  the  upper  lip,  and  raising  the  mucous  membrane  on  the  side  of  the 
frsenum  of  the  lip;  it  arises  from  the  alveoli  of  the  canine  and  incisor  teeth 
of  the  superior  maxilla,  ascends  obliquely  forwards,  and  is  inserted  into  the 
integuments  of  the  upper  lip,  and  into  the  fibro-cartilage  of  the  septum  and 
ala  nasi ; use,  to  press  the  lip  against  the  anterior  teeth,  and  even  to  draw  it 
under  these,  also  to  depress  the  septum  and  ala  nasi. 

Depressor  Anguli  Oris,  flat  and  triangular,  arises  broad  and  fleshy  from 
the  external  oblique  line  on  the  outer  side  of  the  lower  jaw,  extending  from 
the  anterior  edge  of  the  masseter  muscle  to  the  mental  foramen ; the  fibres 
ascend  converging,  and  are  inserted  narrow,  into  the  commissure  of  the  lips ; 
its  name  denotes  its  use.  This  muscle  is  covered  by  the  skin,  some  of  its 
fibres  are  continuous  with  those  of  the  platisma  myoides;  it  overlaps  the  buc 
cinator  and  the  following  muscle. 

Depressor  Labii  Inferioris,  broad  and  somewhat  square,  arises  from  the 
side  and  front  of  the  lower  maxilla,  just  above  its  basis,  and  continues  as  far 
forwards  as  the  middle  line  ; the  fleshy  fibres  intermixed  with  fat,  ascend  a 
little  inwards,  decussating  with  some  of  the  opposite  muscle,  and  are  inserted 
into  half  of  the  lower  lip,  and  into  the  orbicularis  oris;  its  name  denotes  its 
use.  This  muscle  is  covered  by  the  skin,  and  partly  bv  the  depressor  anguli 
oris  ; by  separating  these  muscles  the  mental  nerve  and  vessels  are  exposed  ; 
it  lies  on  the  mucous  membrane,  and  on  the  following  muscle. 

Levator  Lanii  Inferioris,  is  exposed  by  turning  down  the  lower  lip,  and 
raising  the  mucous  membrane  by  the  side  of  the  frsenum;  arises  from  the 
alveoli  of  the  incisor  teeth  of  the  lower  maxilla,  by  the  side  of  the  symphisis  ; 


6 


THE  DUBLIN  DISSECTOR, 


the  fibres  diverge  as  they  descend  obliquely  forwards  between  the  mucous 
membrane  and  the  depressor  labii  inferioris ; inserted  into  the  integuments 
of  the  chin;  use,  to  elevate  the  chin  and  lower  lip:  this  muscle  is  analogous 
to  the  depressor  of  the  upper  lip. 

Orbicularis  Oris,  surrounds  the  opening  of  the  mouth ; consists  of  two 
fleshy  fasciculi,  one  for  either  lip,  placed  between  the  skin  and  mucous  mem- 
brane, and  constituting  the  chief  thickness  of  the  lip;  these  fasciculi  decus- 
sate each  other  at  the  commissures,  and  intermix  with  all  the  muscles  inserted 
there;  use,  to  approximate  the  lips  and  regulate  their  motions  in  the  act  of 
speaking,  also  to  close  the  mouth,  and  to  oppose  the  action  of  the  several 
muscles  which  are  inserted  into  the  commissures.  This  muscle  has  no  bony 
attachment;  its  fibres  are  blended  with  fat,  particularly  on  their  cutaneous 
surface  ; internally  they  are  more  smooth  and  distinct. 

Buccinator,  is  broad,  thin,  and  somewhat  square  ; arises  posteriorlv  from 
the  two  last  alveoli  of  the  superior  maxilla,  as  far  back  as  the  pterygoid  pro- 
cess, from  the  external  surface  of  the  posterior  alveoli  of  the  lower  maxilla, 
as  far  back  as  the  coronoid  process,  and  form  a strong  aponeurosis,  named  the 
intermaxillary  ligament,  which  extends  from  the  pterygoid  plate  to  the  root  of 
the  coronoid  process,  and  which  affords  attachinentto  the  superior  constriction 
of  the  pharynx  posteriorly,  and  to  the  buccinator  anteriorly.  From  these  three 
origins  the  fibres  pass  horizontally  forwards,  converging  a little,  and  are 
inserted  into  the  commissure  of  the  lips,  where  they  intermix  with  those  of 
the  orbicularis  and  the  other  muscles  at  the  angle  of  the  mouth.  Use,  to  press 
the  cheek  against  the  teeth,  so  as  to  push  the  food  between  them,  and  diminish 
the  cavity  of  the  mouth;  also  to  retract  the  commissure  of  the  lip.  The 
buccinator  is  covered  by  a considerable  quantity  of  fat,  which  often  extends 
in  the  form  of  large,  soft,  round  masses  beneath  the  masseter  muscle; 
also  by  the  zygomatic  and  depressor  anguli  oris  muscles  ; several  branches 
of  the  facial  artery  and  vein,  and  of  the  seventh  and  fifth  pair  of  nerves 
ramify  on  its  surface,  it  lies  on  the  mucous  membrane,  and  on  a number  of 
small  round  mucous  glands  called  buccal ; this  muscle  is  perforated  near  its 
superior  posterior  third  by  the  duct  of  the  parotid  gland,  opposite  the  third 
superior  molar  tooth. 

The  deep  muscles  of  the  face,  which  are  connected  with  the  lower  maxilla, 
and  are  employed  in  the  process  of  mastication,  and  the  masseter,  temporal, 
internal,  and  external  pterygoid  of  each  side;  previous  to  dissecting  these, 
the  student  should  examine  the  situation  and  connection  of  the  parotid  gland, 
one  of  the  salivary  glands.  There  are  six  salivary  glands,  three  on  each 
side,  the  parotid,  submaxillary,  and  subtingual. 

The  Parotid  Gland  is  the  largest  of  these  conglomerate  glands;  it  derive? 
its  name  from  its  proximity  to  the  ear ; it  is  exposed  by  dissecting  off  the  in- 
teguments, and  a dense  fascia  which  covers  and  adheres  to  it : this  fascia  is 
continued  from  that  of  the  neck,  spreads  over  the  gland,  is  closely  connected 
to  the  cartilaginous  part  of  the  meatus  auditorius,  and  sends  numerous  pro- 
cesses into  the  gland  in  every  direction,  serving  to  separate  its  lobules  and  to 
conduct  the  different  vessels  through  its  substance.  The  parotid  gland  is  of 
an  irregular  square  figure,  and  of  a pale  color,  filling  the  space  between  the 
ramus  of  the  inferior  maxilla  and  the  ear,  bounded  above  bv  the  zygoma, 
below  by  a line  drawn  from  the  angle  of  the  jaw  to  the  mastoid  process, 


OR  MANUAL  OF  ANATOMY. 


7 


posteriorly  by  the  meatus  auditorius,  the  mastoid  process  and  sterno  mastoid 
muscle,  anteriorly  by  the  masseter  muscle,  the  posterior  third  of  which  it 
overlaps.  Its  external  surface  is  rather  flat,  but  the  internal  is  very  irregular ; 
it  sinks  in  behind  the  jaw,  fills  the  deep  excavation  between  this  bone  and  the 
ear,  rests  against  the  styloid  process  of  the  temporal  bone,  the  internal  carotid 
artery,  jugular  vein,  and  the  large  nerves  connected  with  these  vessels ; it 
also  fills  the  posterior  part  of  the  glenoid  cavity  in  the  temporal  bone,  and 
adheres  to  the  capsular  ligament  of  the  maxilla,  and  interiorly  it  is  wedged  in 
between  the  internal  pterygoid,  digastric  and  styloid  muscles.  The  external 
carotid  artery  and  several  of  its  branches,  with  their  accompanying  veins  and 
branches  of  the  inferior  maxillary  and  cervical  nerves,  pass  through  this  gland ; 
the  plexus  of  the  portio  dura,  or  facial  nerve,  also  traverses  it  from  behind 
forwards,  and  gives  off  numerous  branches  in  its  substance : this  plexus  is 
superficial  to  the  artery,  and  in  some  cases  between  it  and  the  veins.  Several 
absorbent  glands  are  connected  to  it,  particularly  to  its  inferior  part ; fre- 
quently one  or  two,  very  small,  may  be  found  imbedded  in  its  substance  in 
front  of  the  meatus  auditorius.  From  the  anterior  and  superior  part  of  the 
gland  there  passes  forwards  a small  white  tube,  called  Steno\s  duct,  or  the 
parotid  duct ; this  duct  arises  from  the  union  of  numerous  small  tubes,  which 
issue,  each,  from  one  of  the  granulations  of  the  gland;  it  passes  forwards 
over  the  masseter  muscle  about  an  inch  below  the  zygoma,  parallel  to  a line 
drawn  from  the  tube  of  the  ear  towards  the  tip  of  the  nose;  it  winds  round 
the  anterior  edge  of  the  masseter,  beneath  the  zygomatic  muscles  and  through 
a quantity  of  soft  adeps,  pierces  the  buccinator,  and  opens  through  the  mucous 
membrane  of  the  mouth  by  a very  small  hole  opposite  the  2d  or  3d  superior 
molar  tooth,  about  half  an  inch  from  the  junction  of  the  cheek  with  the  gum. 
Between  the  duct  and  the  zygoma,  a small  glandular  mass  is  frequently 
found;  it  appears  like  a detached  lobe  of  the  parotid,  it  is  named  the  socia 
parotidis  ; from  the  lower  and  anterior  part  of  this  process,  a small  duct  pro- 
ceeds, which  after  a short  course  unites  with  the  duct  of  Steno  ; in  some  this 
duct  opens  distinctly  into  the  mouth.  The  transverse  artery  of  the  face,  and 
several  branches  of  the  facial  nerve,  accompany  this  vessel,  and  in  general  the 
artery  is  superior  to  it,  while  the  nerves  wind  around  it. 

The  parotid  gland  is  composed  of  numerous  small  granulations,  united 
together  by  cellular  tissue,  and  by  branches  of  blood-vessels  and  nerves,  and 
by  the  small  roots  of  its  excretory  duct.  This  duct  appears  much  larger  than 
its  calibre  really  is ; it  is  formed  of  two  coats,  the  external,  white,  fibrous 
and  dense,  commences  beyond  the  anterior  edge  of  the  gland,  and  ends  at  the 
buccinator  muscle,  and  the  internal,  a fine  delicate  mucous  membrane,  is 
continuous  with  that  lining  the  mouth  : the  canal  is  larger  at  the  commence- 
ment and  at  the  buccinator  than  in  the  intervening  space,  or  at  the  orifice  in 
the  mouth. 

Divide  the  parotid  duct,  and  raise  off  the  gland  from  the  mastoid  muscle, 
and  from  the  ramus  of  the  jaw,  observing  at  the  same  time  its  several  deep- 
seated  connections.  Next  clean  the  masseter  muscle  and  the  temporal  apon- 
eurosis. 

Masseter  is  thick  and  strong,  covers  the  ramus  and  angle  of  the  jaw,  and 
consists  of  two  portions,  one  anterior,  the  other  posterior ; these  decussate 
each  other ; the  anterior  arises  chiefly  tendinous  from  the  superior  maxilla. 


8 


THE  DUBLIN  DISSECTOR, 


where  it  joins  the  malar  bone ; also  from  the  inferior  edge  of  the  latter,  the  fibres 
pass  downwards  and  backwards,  and  are  inserted  fleshy  into  the  outer  surface 
of  the  angle  of  the  lower  maxilla.  The  posterior  or  deep  portion  of  the 
muscle  arises  chiefly  fleshy,  from  the  edge  of  the  malar  bone  and  from  the 
zygomatic  arch,  as  far  back  as  the  glenoid  cavity;  the  fibres  descend,  some 
vertically,  others  obliquely  forwards,  and  are  inserted  chiefly  tendinous,  into 
the  external  side  of  the  angle  and  ramus  of  the  jaw,  as  high  as  the  coronoid 
process.  Use,  if  both  portions  act  together,  they  will  elevate  the  lower  jaw, 
if  the  anterior  portion  act  alone,  it  will  carry  the  jaw  forwards  and  upwards  ; 
and  if  the  posterior  act  alone  it  will  move  it  backwards  and  upwards.  Thus 
the  masseter  muscles  of  opposite  sides,  by  the  alternate  action  of  their  different 
portions,  are  powerful  agents  in  mastication  ; they  not  only  cause  the  division 
of  the  food  by  the  direct  elevation  and  pressure  of  the  lower  maxilla  against 
the  upper,  but  they  can  also  triturate  it,  by  the  great  lateral  motion  of  the 
jaw  which  they  are  capable  of  exerting.  The  masseter  is  covered  by  the 
skin,  some  fibres  of  the  platisma,  a portion  of  the  parotid  gland,  its  excretory 
duct,  and  accompanying  vessels  and  nerves,  and  by  the  zygomatic  muscles. 
It  lies  on  the  ramus  of  the  jaw,  and  conceals  the  insertion  of  the  temporal 
and  the  origin  of  the  buccinator,  from  which  it  is  separated  by  a great  quantity 
of  fat;  the  superficial  layer  covers  the  deep  one,  except  a small  portion  of 
the  latter  near  the  articulation  of  the  maxilla  ; strong  tendinous  septa  pass 
f rom  the  surface  of  this  muscle  through  its  substance,  and  adhere  to  the  ramus 
of  the  bone  beneath. 

Temporalis,  is  concealed  by  the  temporal  aponeurosis,  the  zygoma,  and 
the  masseter.  The  aponeurosis  is  very  strong  and  tense,  of  a semicircular 
form,  adhering  by  its  superior  convex  border  to  the  semicircular  ridge  on  the 
side  of  the  cranium,  which  extends  from  the  external  angular  process  of  the 
frontal  as  far  back  as  the  mastoid  process  of  the  temporal  bone,  and  by  its  in- 
ferior straight  margin  to  the  upper  edge  of  the  zygoma;  this  fascia  consists  of 
two  laminae,  which  are  very  distinct  inferiorily,  some  fat  being  interposed  ; 
the  fibres  composing  the  external  layer  run  longitudinally,  those  of  the  internal 
irregularly.  The  temporal  aponeurosis  confines  the  muscle  in  its  place,  and 
gives  additional  origin  to  its  fibres.  Separate  the  masseter  from  its  superior 
attachment,  divide  with  the  saw  the  zygoma  at  either  end,  and  elevate  it  to- 
gether with  the  lower  part  of  the  temporal  fascia;  the  temporal  muscle  will 
be  thus  exposed.  It  arises  from  all  the  side  of  the  cranium  beneath  the  semi- 
circular ridge  on  the  parietal  bone,  and  from  all  the  temporal  fossa  and  fascia  ; 
the  fibres,  therefore,  are  attached  internally  to  the  parietal,  frontal,  and  tem- 
poral bones,  also  to  the  sphenoid  as  low  down  as  the  crest  at  the  root  of  its 
great  wing;  anteriorly  to  the  malar  bone,  and  externally  to  the  inside  of  the 
temporal  fascia,  and  to  the  zygomatic  arch.  The  fleshy  fibres  all  descend 
converging;  the  middle  nearly  vertical ; the  anterior  with  a little  obliquity 
backwards;  the  posterior,  which  are  very  long,  pass  nearly  horizontally  for- 
wards, over  a smooth  surface  at  the  root  of  the  zygoma,  and  the  inferior  fibres, 
which  arise  from  the  crest  on  the  sphenoid  bone  are  very  short,  and  past  trans- 
versely outwards. 

Inserted  by  a strong  tendon  into  the  coronoid  process  of  the  inferior  maxilla ; 
it  surrounds  that  process,  and  is  continued  along  its  fore  part  as  far  as  the 
last  molar  tooth.  Use,  to  raise  the  lower  jaw  when  the  whole  muscle  acts; 


OR  MANUAL  OF  ANATOMY. 


9 


the  anterior  fibres  may  also  advance  the  jaw,  and  the  posterior  long  fibres  can 
draw  it  backwards,  while  the  inferior  transverse  fibres,  which  are  nearly 
parallel  to  the  external  pterygoid  muscle,  may  assist  in  the  lateral  and  rota- 
tory motions  of  the  jaw ; this  muscle,  particularly  its  posterior  portion,  is  the 
greatest  security  which  the  jaw  possesses  against  dislocation.  The  temporal 
muscle  is  covered  by  the  integuments,  occipito  frontalis,  superficial  temporal 
vessels  and  nerves,  temporal  fascia,  zygoma  and  masseter ; it  lies  on  the  side 
of  the  cranium,  and  covers  the  deep  temporal  vessels,  and  part  of  the  external 
pterygoid  and  buccinator  muscles.  The  temporal  muscle  consists  of  two 
laminae  of  fleshy  fibres,  with  an  aponeurosis  or  tendon  concealed  between 
them. — Remove  the  temporal,  masseter  and  buccinator  muscles,  also  the 
zygomatic  arch,  saw  or  break  off,  low  down,  the  coronoid  process,  dissect 
away  some  fat,  and  the  pterygoid  muscles  will  be  exposed,  the  dissection  of 
which  may  be  still  further  facilitated  by  dividing  the  side  of  the  lower  jaw  in 
front  of  the  insertion  of  the  masseter,  and  then  drawing  the  angle  and  ramus 
backwards  and  forwards. 

Pterygoideus  Internus  is  strong  and  thick,  placed  on  the  inner  side  of 
the  ramus  of  the  jaw,  arises  tendinous  and  fleshy  from  the  inner  side  of  the 
external  pterygoid  plate,  and  pterygoid  process  of  the  palate  bone  ; it  fills  the 
greater  part  of  the  pterygoid  fossa,  descends  obliquely  outwards  and  back- 
wards, and  is  inserted  tendinous  and  fleshy  into  the  inner  side  of  the  angle  of 
the  jaw,  and  into  the  rough  surface  above  it.  Use , to  elevate  the  jaw,  if  the 
muscles  of  the  opposite  side  act  together  ; if,  alternately,  they  can  rotate  it, 
each  moving  the  jaw  laterally,  so  as  to  turn  it  to  the  opposite  side.  This 
muscle  is  larger  than  the  external  pterygoid,  inferior  and  external  to  which 
it  lies,  the  term  internal  only  referring  to  the  relation  of  its  origin.  The  ten- 
sor palati,  superior  constrictor,  and  submaxillary  gland,  are  in  contact  with  it 
internally  : the  ramus  of  the  jaw  is  external  to  it,  and  separated  from  it  by  the 
dental  artery  and  nerve,  which  are  protected  from  the  pressure  of  the  muscle 
by  the  internal  lateral  ligament  of  the  jaw : the  lower  extremity  of  this  muscle 
is  superficial,  and  lies  between  the  parotid  and  submaxillary  glands. 

Pterygoideus  Externus  is  short  and  triangular,  placed  at  the  lower  part 
of  the  temporal  fossa,  arises  broad  and  fleshy  from  the  outer  side  of  the  ex- 
ternal pterygoid  plate,  from  the  crest  on  the  great  wing  of  the  sphenoid,  and 
from  the  back  part  of  the  tuberosity  of  the  superior  maxilla  ; the  fibres  pass 
outwards  and  backwards,  nearly  horizontal  and  converging,  are  inserted, 
tendinous  into  the  anterior  and  internal  part  of  the  neck  of  the  lower  jaw,  and 
of  the  interarticular  cartilage.  Use,  to  draw  forward  the  jaw  and  interarticular 
cartilage  ; if  only  one  act,  it  will  turn  the  jaw  to  the  opposite  side,  so  as  to 
triturate  or  grind  the  food.  These  muscles  are  the  chief  agents  in  producing 
dislocation  of  the  jaw;  when  the  mouthis  widely  opened  their  spasmodic  ac- 
tion may  suddenly  draw  the  condyles  forwards  off  the  tubercles  into  the 
zygomatic  fossae.  The  external  pterygoid  muscle  lies  in  a transverse  direc- 
tion beneath  the  base  of  the  cranium,  and  much  further  from  the  surface  than 
the  internal  pterygoid,  superior  to  which  it  lies  ; it  is  internal,  and  inferior  to 
the  temporal  muscle,  and  is  also  concealed  by  the  masseter.  As  the  external 
and  internal  pterygoid  muscles  arise  so  near  each  other,  and  thence  pass  in 
different  directions  to  their  insertion,  the  external  going  transversely,  and  the 
internal  descending,  they  leave  between  them  a triangular  space,  which 


10 


THE  DUBLIN  DISSECTOR, 


contains  a quantity  of  fat,  a small  portion  of  the  parotid  gland,  the  internal 
maxillary  artery  and  vein,  and  the  dental  and  gustatory  branches  of  the  inferior 
maxillary  nerve. 

§ 3. — Vessels  and  Nerves  of  the  Face. 

The  arteries  which  are  to  be  met  with  in  the  dissection  of  this  region,  are 
the  facial  and  the  terminating  branches  of  the  external  carotid  ; the  nerves  are 
branches  of  the  7th  and  5th  pair.  The  facial  artery  which  is  a branch  of 
the  external  carotid,  is  seen  winding  round  the  side  of  the  jaw,  anterior  to  the 
masseter,  and  running  in  a contorted  course  towards  the  commissure  of  the 
lips,  and  thence  ascending  along  the  side  of  the  nose  to  the  internal  canthus 
of  the  eye,  in  this  course  it  sends  off,  numerous  muscular  branches,  the 
coronary  arteries  of  the  Ups,  the  nasal  branches,  and  terminates  in  the 
angular  branch  which  communicates  with  the  ophthalmic  artery  at  the  in- 
ner side  of  the  orbit.  The  facial  artery  and  its  divisions  are  accompanied  by 
corresponding  veins  ; the  facial  vein  at  the  lower  edge  of  the  jaw,  generally, 
but  not  always,  divides  into  two  branches,  one,  superficial,  joins  the  external 
jugular  vein,  the  other  passing  deeper  in  the  neck,  joins  the  internal  jugular. 
The  external  carotid  artery,  which  is  seen  ascending  from  the  neck  into 
the  parotid  gland,  gives  off  numerous  branches  to  its  several  lobules,  and  to 
the  ear,  and  a little  below  the  latter  divides  into  the  transversalis  faciei,  tem- 
poralis superficialis  and  maxillaris  interna.  The  transverse  artery  of  the 
face  crosses  the  masseter  above,  sometimes  below  the  parotid  duct,  and  di- 
vides into  small  muscular  branches,  some  of  which  communicate  with  the 
facial  and  infraorbital  arteries.  The  temporal  artery  ascends  behind  the 
articulation  of  the  maxilla  on  the  temporal  aponeurosis,  and  soon  divides  into 
an  anterior  and  posterior  branch  ; the  former  is  directed  towards  the  forehead, 
supplies  the  integuments  and  muscles  there,  and  communicates  with  the  fron- 
tal branches  of  the  ophthalmic  artery ; the  posterior  division  of  the  temporal 
runs  tortuously  upwards  and  backwards,  and  divides  into  numerous  branches, 
which  supply  the  integuments  and  inosculate  with  the  occipital  and  posterior 
auris  arteries.  The  internal  maxillary  artery  is  the  largest  branch  of 
the  carotid  ; it  bends  in  behind  the  neck  of  the  lower  jaw,  between  the  bone 
and  the  internal  lateral  ligament,  then  runs  tortuously  between  the  pterygoid 
muscles,  upwards,  forwards,  and  inwards  to  the  lower  and  back  part  of 
the  orbit,  where  it  sinks  into  the  spheno-maxillary  fossa;  in  this  course 
it  sends  off  the  middle  artery  of  the  dura  matter,  the  inferior  dental,  several 
muscular  branches  to  the  temporal,  masseter,  pterygoid  and  buccinator 
muscles,  and  terminates  by  dividing  into  the  nasal,  descending  palatine, 
and  infraorbital  arteries.  Veins  accompany  these  different  arteries,  and 
in  the  parotid  gland  we  find  the  temporal  and  intermaxillary  veins  forming, 
by  their  junction,  a considerable  vessel  called  the  external  jugular  vein, 
which  will  be  afterwards  seen  descending  superficially  in  the  neck.  (For  the 
particular  description  of  the  blood-vessels  of  the  face,  see  the  Anatomy  of 
the  Vascular  System.) 

The  nerves  which  are  met  with  in  the  dissection  of  the  face  are  branches 
of  the  7th  and  5th  pair;  those  of  the  7th,  or  the  portio  dura,  have  in  general 
a transverse  direction  from  behind  forwards,  are  remarkable  for  their 


OR  MANUAL  OF  ANATOMY. 


11 


plexiform  arrangement,  and  have  numerous  communications  with  the  three 
branches  of  the  5th,  which  are  distributed  chiefly  in  a vertical  direction  along 
the  anterior  part  of  the  face.  Th e.  portio  dura  escapes  from  the  temporal  bone 
through  the  stylomastoid  hole,  turns  forwards  into  the  parotid  gland,  in  which 
it  divides  into  two  large  branches,  which  subdivide  and  join  again  by  several 
filaments  forming  the  plexus,  named  pes  anserinus,  or  parotidsean  plexus , 
from  which  several  nerves  proceed ; some  ascend  obliquely  forwards  to  the 
temple  and  forehead,  others  pass  transversely  to  the  muscles  of  the  face,  and 
several  descend,  some  parallel,  and  others  inferior,  to  the  side  of  the  lower 
maxilla. 

The  5th  pair  of  nerves  consists  of  three  portions,  viz.,  the  ophthalmic, 
superior  maxillary,  and  inferior  maxillary;  a branch  of  each  of  these  divi- 
sions is  met  with  in  the  dissection  of  the  face.  The  frontal  nerve,  which  is 
a branch  of  the  ophthalmic,  or  first  division  of  the  5th,  is  seen  escaping  from 
the  orbit  by  the  superciliary  notch  or  foramen ; it  then  ascends  on  the  fore- 
head, distributes  its  branches  to  the  integuments  and  muscles,  and  communi- 
cates with  the  portio  dura.  The  infra-orbital  nerve,  which  is  a branch  of  the 
superior  maxillary,  or  second  division  of  the  5th,  is  observed  passing  out  of 
the  infra-orbital  foramen,  behind  the  levator  labii  superioris  alrnque  nasi,  and 
dividing  into  several  branches ; the  most  of  these  pass  obliquely  downwards, 
and  communicate  freely  with  branches  of  the  7th  pair.  Through  the  mental 
foramen  the  mental  nerve  escapes ; this  is  a branch  of  the  inferior  maxillary, 
or  third  division  of  the  5th  pair;  most  of  its  branches  ascend  to  the  muscles 
of  the  lower  lip,  and  several  communicate  with  the  portio  dura. — (For  the 
more  particular  description  of  the  nerves  of  the  face,  see  the  Anatomy  of  the 
Nervous  System.) 

The  mouth,  fauces,  and  palate,  are  the  parts  of  the  face  next  in  order  to 
be  examined ; but  as  these  are  connected  and  continuous  with  the  pharynx, 
and  as  this  organ  cannot  be  seen  until  the  muscles  of  the  neck  have  been  re- 
moved, the  student  had  better  postpone  the  dissection  of  the  former  until  he 
has  become  acquainted  with  the  anatomy  of  the  latter;  we  shall  therefore 
proceed  next  to  the  dissection  of  the  neck. 


CHAPTER  II. 

DISSECTION  OF  THE  NECK. 

§1. — Of  the  Muscles. 

Raise  the  shoulders  of  the  subject  by  blocks  placed  beneath  them,  so  as  to 
make  tense  the  muscles  in  this  region  ; divide  the  integuments  near  to,  and  in 
a line  with  the  clavicle,  also  along  the  side  of  the  jaw  from  the  chin  to  the 
mastoid  process;  connect  these  incisions  by  another  made  in  a perpendicular 
direction,  in  the  middle  line  from  the  chin  to  the  sternum ; dissect  off  the 
integuments  from  before  backwards,  in  an  oblique  direction,  from  the  chin 
towards  the  clavicle ; this  should  be  done  cautiously,  to  avoid  injuring  the 
platysma  or  fascia.  The  platysma  myoides  will  be  now  fully  exposed,  and 
the  sterno-mastoid  and  hyoid  muscles  partially  so  ; in  the  middle  line  of  the 
neck  a chain  of  projections  may  be  observed,  which  can  also  be  felt  during 


12 


THE  DUBLIN  DISSECTOR, 


life,  viz.  a little  below,  but  at  some  distance  behind  the  chin,  is  the  body  of 
the  os  hyoides;  inferior  to  this  is  the  angle  of  the  thyroid  cartilage;  next  is 
the  cricoid,  below  which  the  commencement  of  the  trachea  may  be  felt,  on 
the  forepart  of  which  the  soft  swelling  of  the  thyroid  gland  can  be  discerned: 
and  lastly,  the  continuation  of  the  trachea  descending  into  the  chest. 

Platysma-myoides,  or  latissimus  colli,  is  a thin  cutaneous  muscle,  in  many 
subjects  weak,  and  even  indistinct;  its  figure  is  somewhat  square,  being  a 
little  longer  than  it  is  broad  ; it  arises  by  many  fine  fleshy  fibres  from  the  cel- 
lular membrane,  covering  the  upper  part  of  the  deltoid  and  pectoral  muscles  ; 
a few  also  adhere  to  the  clavicle;  the  fibres  ascend  obliquely  inwards,  ai  first 
loosely,  afterwards  closely  connected  to  each  other,  and  form  a broad  thin 
muscle,  covering  the  side  of  the  neck,  inserted  1st,  into  the  chin,  decussating 
there  with  fibres  from  the  opposite  side;  2d,  into  the  fascia  along  the  side  of 
the  lower  jaw,  a few  only  into  the  bone  ; some  fibres  may  be  traced  high  on 
the  face,  and  seen  to  join  the  depressor  anguli  oris,  the  zygomatic  and  orbi- 
cularis palpebrarum  muscles;  and  3d,  into  the  fascia,  which  covers  the  pa- 
rotid, and  which  adheres  to  the  meatus  auditorius.  Use,  to  depress  the  angle 
of  the  lips  and  the  lower  jaw,  but  if  the  mouth  be  closed  it  may  elevate  the 
integuments  of  the  neck;  it  also  serves  to  compress  and  support  the  several 
muscles,  glands,  and  vessels  in  this  region.  The  platysma  is  covered  only 
by  the  skin;  it  partly  conceals  the  clavicle,  the  sterno-mastoid,  hyoid,  and 
thyroid  muscles;  also  the  digastric  and  stylo-hyoid,  the  sub-maxillary  gland, 
and  lower  part  of  the  parotid;  also,  in  part,  the  external  jugular  vein:  this 
vein  commences  in  the  parotid  gland,  descends  obliquely  outwards  over  the 
sterno-mastoid  muscle,  where  it  lies  very  superficial,  and  then  sinks  behind 
the  clavicle,  and  joins  the  subclavian  vein  or  some  of  its  branches.  The 
upper  portion  of  the  external  jugular  vein  is  accompanied  by  a large  nerve, 
superjicialis  colli,  a branch  of  the  cervical  plexus  ascending  to  the  parotid 
gland  and  external  ear. 

This  vein  in  its  course  down  the  neck  receives  several  cutaneous  veins,  and 
frequently  communicates  with  the  internal  jugular : it  presents  great  varieties 
in  its  size  and  course,  and  is  sometimes  even  wanting.  Superficial  veins  may 
also  in  general  be  marked  descending  along  the  anterior  part  of  the  neck  ; 
they  arise  about  the  os  hyoides  and  upper  part  of  the  thyroid  gland,  and 
descend  beneath  some  fibres  of  the  platysma  along  the  anterior  edge  of  the 
mastoid  muscle,  and  end  in  the  internal  or  external  jugular,  or  in  the  venae 
inominatse.  The  fibres  of  the  platysma  are  closely  connected  to  a layer  of 
condensed  cellular  tissue,  which  in  some  subjects  is  very  strong,  and  in  some 
situations  aponeurotic  ; this  is  the  superficial  cervical  fascia ; this  fascia  ex- 
tends over  the  anterior  and  lateral  parts  of  the  neck  ; is  continued  down  over 
the  forepart  of  the  thorax,  where  it  becomes  cellular  and  adipose  ; ascends  to 
the  jaw,  to  which  it  is  attached  ; expands  over  the  parotid  gland  and  adheres 
to  the  cartilage  of  the  ear;  in  this  situation  its  strength  is  greatly  increased  : 
towards  the  lateral  and  posterior  parts  of  the  neck  it  becomes  weak  like  cel- 
lular membrane.  From  the  posterior  surface  of  this  fascia  a lamina  of  mem- 
brane is  derived,  which  passes  behind  the  sterno-mastoid  muscle  : this  is  the 
deep  cervical  fascia,  which  has  some  important  connections,  which  may  be  ex- 
amined in  this  stage  of  the  dissection : The  deep  fascia  arises  from  the  super- 
ficial, along  the  anterior  edge  of  the  sterno-mastoid  muscle,  posterior  to  which 


OR  MANUAL  OF  ANATOMY. 


13 


it  passes,  so  that  this  muscle  is  enclosed  between  these  membranes : at  the 
lower  part  of  the  neck  it  is  strong,  and  adheres  to  the  inter-clavicular  liga- 
ment and  posterior  edge  of  the  sternum.  Some  loose  fatty  substance  is  here 
interposed  between  it  and  the  superficial  fascia:  as  the  deep  fascia  extends 
upwards,  it  covers  and  adheres  to  the  sheath  of  the  cervical  vessels,  and 
arriving  at  the  space  between  the  trapezius  and  mastoid  muscles,  it  becomes 
weak  and  cellular,  inferiorly  accompanying  the  great  vessels  beneath  the 
clavicle,  and  superiorly  lost  on  the  branches  of  the  cervical  plexus  of  nerves  ; 
at  the  superior  and  lateral  parts  of  the  neck  it  sinks  deep,  behind  the  angle  of 
the  jaw,  to  which  it  adheres,  and  is  connected  to  the  styloid  process  of  the 
temporal  bone,  and  to  the  stylo-maxillary  ligament:  absorbent  glands,  the 
lower  part  of  the  parotid,  and  much  cellular  membrane  here  lie  between  these 
two  fasciee.  In  this  situation  collections  of  matter  often  form,  the  result  of 
cynanche  parotidaea,  or  of  inflammation  of  some  of  the  lymphatic  glands: 
such  collections  are  productive  of  great  inconvenience,  causing  such  swelling 
and  tension  as  to  interfere  with  the  motions  of  the  jaw,  and  with  the  act  of 
deglutition.  The  cervical  fasciae  bind  down  the  muscles  and  support  the  ves- 
sels and  glands  in  this  region  ; at  the  lower  part  of  the  neck  they  serve  to 
protect  the  trachea  and  the  upper  part  of  the  thorax  from  the  pressure  of  the 
atmosphere  during  inspiration.  Dissect  off  the  platysma  and  superficial 
fascia,  and  examine  the  subjacent  muscles. 

Sterno-Cleido  Mastoideus,  long  and  flat,  placed  at  the  anterior  and  late- 
ral part  of  the  neck,  arises  by  a strong  flat  tendon  with  fleshy  fibres  posterior 
to  it,  from  the  upper  and  anterior  part  of  the  first  bone  of  the  sternum,  also 
by  short  aponeurotic  and  fleshy  fibres  from  the  upper  and  anterior  edge  of  the 
sternal  third,  sometimes  half  of  the  clavicle;  a small  triangular  space  sepa- 
rates these  two  origins,  through  which  small  vessels  and  some  cellular  mem- 
brane pass  : this  space  corresponds  to  the  sterno-clavicular  articulation. 

The  sternal  and  longer  portion  of  this  muscle  ascends  obliquely  backwards 
and  outwards,  and  overlaps  the  clavicular,  which  ascends  vertically;  about 
the  middle  of  the  neck  they  are  intimately  joined,  and  are  inserted  by  a thin, 
broad  aponeurosis  into  the  upper  part  of  the  mastoid  process,  and  into  the 
external  third  of  the  superior  transverse  ridge  of  the  occipital  bone.  Use, 
the  sternal  portion  can  turn  the  face  and  head  towards  the  opposite  side:  the 
clavicular,  can  bend  the  head  and  neck  to  its  own  side,  so  as  to  approximate 
the  ear  and  shoulder;  and  if  the  two  portions  of  the  muscle  on  each  side  act 
together,  they  will  move  the  head  downwards  and  forwards. 

If  the  muscles  on  the  back  of  the  neck  be  in  action,  so  as  to  fix  the  vertebrae 
and  head,  then  these  muscles  may  assist  in  still  further  extending  the  neck, 
and  carrying  the  head  backwards ; this  appears  to  be  the  case  in  tetanus. 
This  muscle  is  covered  bv  the  integuments,  platysma,  superficial  fascia,  ex- 
ternal jugular  vein,  ascending  branches  of  the  cervical  plexus  of  nerves,  and 
by  a small  portion  of  the  parotid  gland  ; it  conceals  part  of  the  sternum  and 
clavicle,  of  the  sterno-hyoid-thyroid,  omo-hyoid,  and  digastric  muscles,  also 
the  lower  part  of  the  cervical  vessels  and  several  glands  ; the  spinal  acces- 
sory nerve  perforates  this  muscle  a little  above  its  centre,  and  near  its  poste- 
rior surface ; this  nerve  is  a division  of  the  eighth  pair,  it  distributes  small 
branches  to  the  mastoid  and  trapezius  muscles,  and  joins  freely  with  the 


14 


THE  DUBLIN  DISSECTOR, 


cervical  plexus : the  spinal  accessory  does  not  always  perforate,  but  sometimes 
passes  posterior  to  the  mastoid  muscle. 

The  student  may  remark  that  the  two  sterno-mastoid  muscles  bound  a large 
triangular  space  situated  on  the  fore  part  of  the  neck,  the  apex  at  the  sternum, 
the  base  at  the  jaw ; this  is  divided  by  the  mesial  line  into  two  lateral  por- 
tions, which  are  named  the  anterior  lateral  triangles  of  the  neck. 

Between  the  mastoid  and  the  trapezius  muscle  also,  on  each  side,  a large 
triangular  space  is  enclosed,  the  base  formed  by  the  clavicle,  the  apex  by  the 
mastoid  process  ; this  space  is  called  the  posterior  lateral  triangle  of  the  neck. 
Both  these  triangular  regions  may  be  observed  to  be  subdivided  into  two  by 
the  omo-hyoid  muscle,  which  crosses  the  neck  obliquely  from  the  shoulder  to 
the  os-hyoides.  Thus  on  each  side  of  the  middle  line  four  triangular  spaces 
may  be  noticed,  principally  formed  by  the  trapezius,  sterno-mastoid,  and 
omo-hyoid  muscles ; these  triangles  are  distinguished  by  the  terms — 1.  pos- 
terior inferior ; 2.  posterior  superior ; 3.  anterior  inferior ; and  4.  anterior 
superior. 

The  student  should  examine  each  of  these  regions,  and  consider  the  parts 
situated  in  each.  These  spaces  can  be  ascertained  during  life,  and  therefore 
an  accurate  knowledge  of  the  contents  of  each  may  be  of  practical  import- 
ance. 1.  The  posterior  inferior  triangle  is  that  small  space  behind  the  clavi- 
cular portion  of  the  mastoid  muscle,  between  the  clavicle  and  posterior  belly 
of  the  omo-hyoid  muscle:  in  this  space  we  find  the  subclavian  artery,  vein, 
and  brachial  plexus  of  nerves  ; it  is  here  that  the  operation  of  tying  the  sub- 
clavian artery,  in  case  of  axillary  aneurism,  is  recommended  to  be  performed. 
2.  The  posterior  superior  triangle  is  above  the  omo-hyoid  and  between  the 
mastoid  and  trapezius  muscles;  it  contains  the  cervical  plexus  of  nerves, 
several  lymphatic  glands,  and  a great  quantity  of  cellular  membrane.  3.  The 
anterior  inferior  triangle  is  above  the  sternal  third  of  the  clavicle  between 
the  median  line  and  anterior  belly  of  the  omo-hyoid  ; this  space  contains  the 
carotid  artery, ’jugular  vein,  and  accompanying  nerves,  covered  by  the  sterno 
mastoid,  hyoid,  and  thyroid  muscles.  4.  The  anterior  superior  triangle  is 
between  the  sterno-mastoid  and  anterior  belly  of  the  omo-hyoid  muscles  ; the 
apex  is  formed  by  the  decussation  of  these  muscles,  and  is  opposite  the  cricoid 
cartilage  ; the  base  is,  superiorly,  marked  by  the  digastric  muscle  and  lingual 
nerve ; — this  space  also  contains  the  great  vessels  and  nerves  which  here  how- 
ever are  only  superficially  covered,  so  that  in  this  situation  the  operation  of 
tying  the  carotid  artery  can  be  more  easily  effected.  Divide  the  sterno-mas- 
toid muscle  about  its  centre,  and  reflect  each  portion  towards  its  attachment ; 
at  the  lower  part  of  the  neck,  behind  and  between  the  sterno-mastoid  muscles, 
are  seen  the  following : 

Sterno-Hyoideus  is  long,  flat  and  thin,  arises  from  the  posterior  surface 
of  the  first  bone  of  the  sternum,  cartilage  of  the  first  rib,  sternal  end  of  the 
clavicle,  and  sterno-clavicular  capsule  ; ascends  obliquely  inwards,  approxi- 
mating its  fellow  above,  and  is  inserted  into  the  lower  border  of  the  body  of 
the  os  hyoides.  Use,  to  depress  the  os  hjoides,  pharynx  and  larynx.  This 
muscle  is  covered  by  the  sternum  and  clavicle,  by  the  sterno-mastoid  and 
integuments;  it  lies  on  the  sterno-thyroid,  crico-thyroid,  and  thyro-hyoid 
muscles,  and  on  the  thyroid  gland  and  its  vessels;  a tendinous  line  often 


OR  MANUAL  OF  ANATOMY. 


15 


intersects  it  about  its  centre. — Cut  this  muscle  across  and  reflect  each  portion 
towards  its  attachments,  and  we  see  the  following  pair  of  muscles  : 

Sterno-Thyroideus  is  broader  and  shorter  than  the  last,  arises  from  the 
posterior  surface  of  the  sternum  and  cartilage  of  the  second  rib,  ascends 
obliquely  outwards,  and  is  inserted  into  the  oblique  line  on  the  ala  of  the  thy- 
roid cartilage.  Use,  to  depress  the  larynx.  This  muscle  is  covered  by  the 
sterno-mastoid  and  hyoid  muscles,  and  by  the  skin ; it  conceals  the  vena  inpo- 
minata  and  carotid  artery,  the  thyroid  gland,  and  the  trachea;  between  it  and 
the  latter  there  is  a considerable  quantity  of  cellular  membrane  which  con- 
tains several  veins  ( inferior  thyroid  v).  Several  filaments  of  the  descendens 
noni  nerve  are  distributed  to  this  and  to  the  former  muscle.  It  is  between 
the  sterno-thyroid  muscles  that  the  operation  of  tracheotomy  is  performed, 
while  that  of  laryngotomy  is  between  the  sterno-hyoid  muscles  and  between 
the  thyroid  and  cricoid  cartilages. 

Omo  hyoideus  is  long,  slender,  and  digastric,  arises  broad  and  fleshy  from 
the  superior  costa  of  the  scapula  behind  its  semilunar  notch,  from  the  ligament 
covering  that  notch,  sometimes  from  the  base  of  the  coracoid  process,  and 
sometimes  also  from  the  acromial  end  of  the  clavicle ; it  ascends  obliquely 
forwards  a little  above  the  clavicle,  passes  beneath  the  sterno-mastoid  muscle, 
where  it  is  generally  tendinous,  except  in  the  very  young  subject ; becoming 
again  fleshy,  it  ascends  nearly  vertical  along  the  outer  side  of  the  sterno- 
hyoid, and  is  inserted  fleshy  into  the  lower  border  of  the  os  hyoides  at  the 
junction  of  its  body  and  cornu.  Use,  (the  muscle  of  one  side  cannot  act 
independent  of  the  other,)  both  draw  the  os  hyoides,  pharynx,  and  larynx 
downwards  and  backwards,  and  in  deglutition  serve  to  urge  the  food  into  the 
(Esophagus.  The  origin  of  this  muscle  is  concealed  by  the  trapezius ; it  lies 
anterior  to  the  insertion  of  the  levator  anguli  scapulae,  and  between  the  ser- 
ratus  magnus  and  supraspinatus  muscles  : the  posterior  belly  is  covered  only 
by  the  integuments  and  fascia,  and  divides  the  great  posterior  lateral  triangle 
of  the  neck  into  an  inferior  and  superior  part,  as  was  before  mentioned  ; this 
portion  of  the  omo-hyoid  can  frequently  be  distinguished  in  the  living  neck. 
The  tendon  crosses  the  carotid  artery  and  jugular  vein,  and  is  covered  by  the 
sterno-mastoid,  which  can  thus  move  more  easily  on  this  structure.  The 
anterior  belly  and  insertion  are  covered  by  the  integuments  and  fascia,  and 
this  portion  of  the  muscle  divides  the  anterior  lateral  triangle  of  the  neck  into 
an  inferior  and  superior  part.  The  omo-hyoid  crosses  over  the  scaleni  mus- 
cles, the  brachial  plexus,  phrenic,  pneumo-gastric  and  sympathetic  nerves, 
the  carotid  artery,  and  jugular  vein. 

Beneath  the  three  last  described  muscles,  and  lying  on  the  trachea  and  sides 
of  the  larynx,  is  a large,  soft,  red  mass  of  a crescentic  shape,  the  concavity 
directed  upwards ; this  is  tire  thyroid  gland;  it  is  in  general  larger  in  the 
child  than  in  the  adult  or  old,  and  in  the  female  than  in  the  male;  its  size, 
however,  varies  considerably  in  different  individuals  even  of  the  same  sex 
and  age.  It  consists  of  two  large  pyramidal  portions,  called  lateral  lobes, 
connected  together  by  a narrow  slip,  the  middle  lobe;  this  is  thin  and  flat, 
and  closely  connected  to  the  second,  third,  and  fourth  rings  of  the  trachea; 
the  lateral  lobes  are  plump  and  convex,  large  below,  pointed  above,  placed 
by  the  side  of  the  trachea  and  larynx,  and  extending  as  high  as  the  ala  of  the 
thyroid  cartilage ; the  left  lateral  lobe  rests  on  the  oesophagus,  and  both  right 


16 


THE  DUBLIN  DISSECTOR, 


and  left  overlap  the  carotid  artery,  inferior  thyroid  vessels,  and  recurrent 
nerve  ; they  are  covered  by  the  sterno-mastoid,  hyoid,  thyroid,  and  omo-hyoid 
muscles,  by  the  platysma  and  skin ; they  lie  on  the  side  of  the  trachea  and 
larynx,  on  the  crico-thyroid  and  inferior  constrictor  of  the  pharynx.  This 
organ  is  soft  and  spongy,  the  cells  contain  a yellow,  serous,  sometimes  an 
oily  fluid ; it  has  no  excretory  duct,  although  it  is  supplied  by  four  large  arte- 
ries; several  veins,  however,  issue  from  it,  particularly  from  its  inferior  part. 
The  middle  lobe  is  sometimes  deficient;  in  some  cases  it  passes  behind  the 
oesophagus,  or  between  this  tube  and  the  trachea,  a circumstance  which  might 
be  productive  of  great  inconvenience,  and  even  danger,  in  the  event  of  bron- 
chocele  (chronic  enlargement  of  this  gland)  occurring  in  one  in  whom  this 
malformation  existed.  A narrow  slip  is  often  seen  to  ascend  from  the  middle 
lobe  as  high  as  the  os  hyoides.  In  the  infant  the  lower  part  of  the  thyroid  is 
connected  to  the  thymus  gland.  The  use  of  this  organ  is  not  fully  ascer- 
tained. Next  dissect  the  muscles  at  the  upper  part  of  the  neck. 

Digastricus,  placed  at  the  lateral  and  anterior  part  of  the  neck,  thick  and 
fleshy  at  each  extremity,  round  and  tendinous  in  the  centre,  arises  from  a 
groove  in  the  temporal  bone,  internal  to  the  mastoid  process,  descends  obliquely 
forwards  and  inwards,  ends  in  a round  tendon  which  perforates  the  stylo- 
hyoid muscle,  and  is  connected  to  the  cornu  of  the  os  hyoides  by  a dense 
fascia,  sometimes  by  a tendinous  ring  like  a pully ; the  tendon  is  then  re- 
flected upwards  and  forwards,  and  soon  ends  in  the  anterior  fleshy  belly, 
which  continuing  forwards  and  inwards,  is  inserted  into  a rough  depression 
on  the  inner  side  of  the  base  of  the  jaw,  close  to  the  symphysis.  Use,  to 
depress  the  lower  jaw,  and  when  the  mouth  is  closed,  to  elevate  the  os  hyo- 
ides, tongue  and  larynx  ; the  posterior  belly  can  also  draw  these  backwards 
and  upwards,  and  the  anterior  upwards  and  forwards,  so  that  this  muscle  can 
exert  great  influence  in  deglutition;  it  can  also  draw  the  head  backwards,  if 
the  chin  be  fixed.  The  digastric  is  covered  posteriorly  bv  the  sterno-mastoid 
and  splenius,  and  by  a portion  of  the  parotid,  more  anteriorly  by  a few  fibres 
of  the  stylo-hyoideus  and  a small  part  of  the  submaxillary  gland,  by  the  cer- 
vical fascia,  platysma  and  skin  ; it  passes  across  the  styloid  muscles,  the 
external  and  internal  carotid  arteries,  the  8th,  9th  and  sympathetic  nerves; 
also  the  origin  of  the  hyo-glossus  and  insertion  of  the  mylo-hyoid.  In  the 
position  in  which  the  subject  is  placed  during  this  dissection,  this  muscle 
forms  the  inferior  or  convex  border  of  a semicircular  space,  the  superior 
straight  edge  of  which  is  marked  by  the  side  of  the  maxilla,  and  by  a line 
continued  from  its  angle  to  the  mastoid  process  : this  digastric  space  is 
divided  by  the  stylo-maxillary  ligament  into  a posterior  and  anterior  part. 
The  posterior  smaller  one  contains  the  parotid  gland,  the  carotid  artery,  and 
7th  pair  of  nerves;  and  deeper'than  these,  the  styloid  process  and  origin  of 
the  styloid  muscles,  also  the  int-carotid,  jugular  vein,  and  8th,  9th  and  sym- 
pathetic  nerves.  The  anterior  division  of  the  disgastric  space  contains  the 
submaxillary  gland,  the  facial  and  lingual  arteries  ; the  9th  and  gustatorv 
nerves,  several  small  muscles,  which  connect  the  tongue  and  os  hyoides  to 
the  chin,  also  the  sublingual  gland,  which  cannot  be  seen  in  the  present  stage 
of  the  dissection.  The  student  should  examine  the  connections  of  the  sub- 
maxillary gland  before  he  dissects  the  muscles  in  this  region. 

The  submaxillary  is  the  second  of  the  salivary  glands,  of  an  oval  form  and 


OR  MANUAL  OF  ANATOMY. 


17 


pale  color,  surrounded  by  cellular  .membrane  and  several  absorbent  glands, 
covered  by  the  skin,  platysmaand  fascia,  bounded  posteriorly  by  the  digastric 
tendon,  externally  by  the  internal  pterygoid  muscle  and  stylo-maxillary  liga- 
ment; anteriorly  by  the  side  of  the  maxilla,  and  internally  by  the  anterior 
belly  of  the  digastric;  it  rests  on  the  mylostylo-hyoid  and  hyo-glossus  mus- 
cles ; a small  process  of  the  gland  accompanies  its  excretory  duct,  turns  round 
the  posterior  edge  of  that  muscle,  and  lies  between  its  upper  surface  and  the 
membrane  of  the  mouth  ; this  process  frequently  joins  the  sublingual  gland. 
The  facial  artery  and  vein  pass  through  a deep  groove  in  this  gland.  The 
duct  of  this  gland  is  called  Whartonian  duct,  it  arises  by  numerous  fine 
radicles  from  the  lobules  of  the  gland,  leaves  it  at  its  outer  end,  winds  above 
the  mylo-hyoid  muscle,  and  runs  forwards  and  inwards  towards  the  fraenum 
linguae,  by  the  side  of  which  it  opens  into  the  mouth  ; the  orifice  can  be  dis- 
tinctly seen  in  a prominent  papilla,  which  appears  when  the  anterior  part  of 
the  tongue  is  raised  : this  duct  is  about  two  inches  and  a half  long,  is  thia 
and  transparent,  its  coats  are  weaker,  but  its  caliber  is  larger  than  in  Steno’s 
duct:  the  gustatory  nerve  accompanies  this  duct,  at  first  superior  but  after- 
wards inferior  to  it.  Detach  this  gland  from  the  mylo-hyoid,  turn  it  outwards, 
leaving  the  duct  and  deep  process  to  be  further  examined  afterwards ; sepa- 
rate the  anterior  belly  of  the  digastric  from  the  chin,  and  we  see  the  follow- 
ing muscle. 

Mylo-hyoideus,  triangular,  arises  from  the  oblique  line  (the  myloid  ridge,) 
on  the  inner  surface  of  the  side  of  the  maxilla,  which  line  descends  obliquely 
from  beneath  the  last  molar  tooth  towards  the  chin ; the  fibres  descend 
obliquely  inwards  and  backwards  to  the  mesial  line,  and  are  inserted  into  the 
base  of  the  os  hyoides,  and  along  with  its  fellow,  into  a middle  tendinous  line 
between  that  bone  and  the  chin.  Use,  to  elevate  the  os  hyoides  and  tongue, 
so  as  to  press  the  latter  against  the  palate.  This  muscle  was  covered  by  the 
gland,  and  by  the  digastric  ; it  lies  on  the  hyo-glossus,  stylo-glossus,  and 
genio-hyoid  muscles,  and  conceals  the  Whartonian  duct,  the  lingual  and  gus- 
tatory nerves  and  sublingual  gland.  Detach  this  muscle  from  the  os  hyoides 
and  from  its  fellow;  in  the  middle  line  we  shall  then  see  the  following  pair. 

Genio-hyoideus,  short  and  round,  arises  by  a small  tendon  on  the  inner 
side  of  the  chin,  above  the  digastric,  descends  obliquely  backwards,  and  is 
inserted  broad  and  fleshy  into  the  base  of  the  os  hyoides.  Use,  to  draw  the 
os  hyoides  upwards  and  forwards,  to  push  the  tongue  against  the  incisor  teeth, 
or  protrude  it  from  the  mouth  : this  pair  of  muscles  lie  superior  to  the  digas- 
tric and  mylo-hyoid,  and  inferior  to  the  genio-hyo-glossus.  Reflect  the  genio 
and  mylo-hyoid  muscles  towards  the  lower  jaw,  we  thus  expose  superiorly 
the  membrane  of  the  mouth,  with  the  sublingual  gland  attached  to  it,  close  to. 
which  is  the  gustatory  nerve;  inferior  to  this  the  Whartonian  duct  is  seen, 
and  nearer  to  the  os  hyoides  is  the  lingual  nerve,  from  which  a plexus  extends 
to  the  gustatory;  the  hyo  and  genio-hyo-glossi,  and  the  three  styloid  muscles 
are  also  now  exposed.  The  sublingual  is  the  third  and  smallest  of  the  sali- 
vary  glands,  oblong,  placed  beneath  the  anterior  and  lateral  part  of  the 
tongue,  covered  superiorly  by  the  mucous  membrane,  to  which  it  adheres, 
and  resting  inferiorly  on  the  mylo-hyoid,  is  in  contact,  internally,  with  the 
genio-glossus,  and  is  connected  externally  to  the  deep  process  of  the  submax- 
illary  gland.  This  gland  opens  by  several  small  ducts,  some  of  which  joint 


18 


THE  DUBLIN  DISSECTOR, 


the  Whartonian  canal,  others  perforate  the  mucous  membrane  of  the  mouth, 
between  the  tongue  and  inferior  canine,  and  bicuspis  teeth  bj  small  openings, 
which  may  be  observed  on  a sort  of  crest  or  fold  of  the  mucous  membrane  in 
this  situation.  The  three  salivary  glands,  though  generally  separated  from 
each  other,  yet  are  in  some  cases  so  joined  together  as  to  resemble  one  irre- 
gular glandular  mass,  the  parotid  being  united  to  the  submaxillary  behind  the 
angle  of  the  jaw,  and  the  latter  being  connected  to  the  sublingual  around  the 
mylo-hyoid  muscle. 

IIyo-glossus  is  flat  and  thin,  arises  from  the  cornu  and  part  of  the  body 
of  the  os  hyoides,  ascends  a little  outwards,  inserted  into  the  side  of  the 
tongue.  Use,  to  render  the  dorsum  of  the  tongue  convex  bv  depressing  its 
side  ; it  may  also  elevate  the  os  hyoides  and  base  of  the  tongue.  This  muscle 
is  covered  by  the  mylo-hyoid  in  part,  and  by  the  sublingual  gland  and  lingual 
nerve;  it  lies  on  the  middle  constrictor  of  the  pharynx,  the  lingual  artery, 
and  the  substance  of  the  tongue. 

Genio-hyo-Glossus  is  triangular,  arises  by  a small  tendon  from  an  emi- 
nence inside  the  chin,  beneath  the  fraenum  linguae;  thence  the  fibres  radiate, 
the  superior  ascend  and  turn  forwards  towards  the  tip  of  the  tongue,  the 
middle  also  ascend,  some  inclining  forwards,  others  backwards;  the  inferior 
and  posterior  pass  backwards  and  downwards  to  the  base  of  the  os  hyoides. — 
Inserted  into  the  mesial  line  of  the  tongue  from  the  apex  to  the  base,  and 
into  the  body  and  lesser  cornu  of  the  os  hyoides.  Use,  the  posterior  fibres 
can  draw  the  os  hyoides  towards  the  chin  and  push  the  tongue  forwards,  the 
anterior  can  draw  back  the  tongue,  and  bend  its  tip  down  towards  the  fraenum, 
the  middle  portion  can  depress  the  middle  of  the  tongue  and  make  it  concave 
from  side  to  side  ; it  can  also  draw  it  forwards  so  as  to  enlarge  the  opening 
of  the  fauces.  This  muscle  is  therefore  used  in  mastication  and  deglutition, 
also  in  the  articulation  of  several  letters. 

The  several  muscles  last  described  cover  this  muscle  externally;  internally 
it  is  in  contact  with  its  fellow. 

Lingualis  is  a fasciculus  of  fibres  taking  a longitudinal  course  on  the  infe- 
rior surface  of  the  tongue  from  the  base  to  the  apex,  and  intermixing  with  the 
muscles  on  either  side,  so  that  it  appears  as  being  derived  from  these  rather 
than  as  a distinct  muscle  ; the  fibres  are  attached  through  their  whole  length, 
and  are  mixed  with  a soft  fatty  substance ; anteriorly  they  are  broader  and 
more  distinct;  they  are  situated  between  the  genio-hyo-glossus  internally, 
and  the  hyo  and  stylo-glossi  externally.  Use,  to  shorten  the  tongue,  and 
bend  the  tip  downwards  and  to  one  side.  External  to  the  muscles  now  de- 
scribed, we  see  the  three  styloid  muscles. 

Stylo-Hyoideus  crises  from  the  outer  side  of  the  styloid  process  near  its 
base,  descends  obliquely  forwards  parallel  to  the  posterior  belly  of  the  digas- 
tric, whose  tendon  generally  perforates  this  muscle,  inserted  into  the  cornu 
and  body  of  the  os  hyoides  and  into  the  fascia,  which  connects  the  digastric 
tendon  to  this  bone.  Use,  to  co-operate  with  the  posterior  part  of  the  digas- 
tric, in  raising  and  drawing  back  the  os  hyoides  and  tongue.  This  muscle  is 
nearly  superficial,  but  at  first  is  covered  by  the  parotid  ; the  digastric  lies  to 
its  external  side,  and  the  external  carotid  artery  to  its  internal : this  vessel  is 
posterior  to  the  lower  part  of  the  muscle,  but  anterior  to  its  origin  ; a liga- 
ment often  accompanies  the  stylo-hyoid  muscle,  from  the  styloid  process  to 


OR  MANUAL  OF  ANATOMY. 


19 


the  cornu  of  the  os  hyoides ; it  is  named  the  stylo-hyoid  ligament,  and  is 
sometimes  ossified.  Raise  the  digastric  and  stylo-hyoid,  and  we  see  the 
remaining  styloid  muscles. 

Stylo-Glossus  arises  tendinous  and  narrow  from  the  styloid  process  near 
its  point,  and  from  the  stylo -maxillary  ligament;  descends  obliquely  forwards 
and  inwards,  and  is  inserted  into  the  side  of  the  tongue ; its  fibres  overlap 
and  unite  with  those  of  the  hyo-glossus,  and  can  be  traced  as  far  as  the  tip. — 
Use , to  draw  the  tongue  backwards,  and  to  one  side,  and  to  raise  the  tip  be- 
hind the  upper  incisor  teeth.  It  is  covered  by  the  sub-maxillary  and  lingual 
glands,  by  the  gustatory  nerve  and  mucous  membrane. 

Stylo -Pharyngeus,  long  and  narrow,  arises  from  the  back  part  of  the  root 
of  the  styloid  process,  descends  inwards  and  backwards,  passes  between  the 
superior  and  middle  constrictors  of  the  pharynx,  with  which  it  mixes  ; is  in- 
serted with  these  into  the  side  of  the  pharynx,  also  into  the  cornu  of  the  os 
hyoides  and  thyroid  cartilage.  Use,  to  elevate,  dilate,  and  draw  forward  the 
pharynx,  so  as  to  receive  the  food  from  the  tongue.  It  is  covered  by  the  stylo- 
hyoid, middle  constrictor  and  external  carotid,  and  it  lies  on  the  superior 
constrictor,  internal  carotid,  sympathetic  and  parvagum;  the  glosso-pharyn- 
geal  nerve  winds  round  it. 

§ 2. — Dissection  of  the  Vessels  and  Nerves  of  the  Neck. 

The  arteries  which  are  met  with  in  dissecting  the  neck  are  the  carotid  and 
.subclavian  of  each  side,  and  their  several  branches ; the  veins  are  the  external 
and  internal  jugular  and  subclavian  ; the  nerves  are  the  gustatory  branch  of 
the  fifth,  eighth  and  the  ninth  pair,  the  sympathetic  and  the  anterior  branches 
of  the  eight  cervical  and  first  dorsal  spinal  nerves.  The  right  carotid  artery 
arises  from  thearteria  innominata,  behind  the  right  sterno-clavicular  articula- 
tion; the  left  carotid  arises  from  the  upper  part  of  the  arch  of  the  aorta;  in 
other  respects  these  arteries  are  similar;  both  ascend  by  the  side  of  the 
trachea  and  larynx,  surrounded  by  a sheath  of  cellular  membrane,  on  the 
forepart  of  which  are  seen  the  branches  of  the  decendens  noni  nerve  ; behind 
the  sheath  lies  the  sympathetic,  and  within  it  are  the  jugular  vein,  lying  to 
the  outside  of  the  artery,  and  the  par  vagum  nerve,  between,  and  rather  behind 
both  these  vessels ; opposite  the  os  hyoides  each  carotid  divides  into  two 
branches,  viz.  the  internal  and  external ; the  internal  carotid  artery  is  the  larger 
branch,  lies  deeper  in  the  neck,  and  more  external ; it  ascends  along  the  fore- 
part of  the  transverse  processes  of  the  vertebrae  to  the  base  of  the  cranium, 
enters  this  cavity,  through  the  foramen  caroticum  in  the  temporal  bone,  and 
is  distributed  to  the  brain.  The  external  carotid  artery  ascends  towards  the 
parotid  gland,  being  crossed  by  the  digastric  and  stylo-hyoid  muscles,  and  by 
the  lingual  and  portio  dura  nerves  ; in  this  course  it  gives  off  several  branches, 
viz.  the  superior  thyroid,  lingual,  libial  or  facial  auricular,  occipital,  pharyn- 
geal, transverse  facial,  internal  maxillary  and  temporal. 

The  subclavian  arteries  are  situated  at  the  inferior  and  lateral  part  of  the 
neck : the  right  arises  from  the  arteria  innominata,  the  left  from  the  posterior 
part  of  the  arch  of  the  aorta ; each  subclavian  artery  passes  upwards  and 
outwards  to  the  anterior  scalenus,  behind  which  it  passes ; it  then  turns  down- 
wards and  outwards  behind  the  clavicle,  and  over  the  first  rib  into  the  axilla: 


20 


THE  DUBLIN  DISSECTOR, 


the  difference  in  the  origin  causes  an  important  difference  in  the  situation  and 
connections  of  the  right  and  left  subclavian  in  the  early  part  of  their  course, 
the  right  being  shorter  and  nearly  transverse,  lies  higher  in  the  neck,  and 
more  superficial  than  the  left,  which  arises  deep  in  the  thorax,  out  of  which  it 
ascends  perpendicularly  before  it  turns  outwards  to  pass  between  the  scaleni ; 
after  this  point,  these  vessels  are  similar  in  every  respect ; each  gives  off  the 
following  branches,  viz.  arteria  vertebralis,  mammaria  interna,  axis  thyro- 
idea,  cervicalis  profunda,  and  intercostalis  superior. 

The  external  jugular  vein  has  been  already  noticed  ; the  internal  jugular 
vein  of  each  side  commences  at  the  termination  of  the  lateral  sinus  in  the 
foramen  lacerum  posterius,  descends  along  the  outer  side,  first,  of  the  internal, 
and  afterwards  of  the  common  carotid  artery,  and  at  the  inferior  part  of  the 
neck  joins  the  subclavian  vein,  which  returns  the  blood  from  the  upper  ex- 
tremity, and  accompanies  the  subclavian  artery;  the  junction  of  each  jugular 
and  subclavian,  which  is  posterior  to  the  sternal  end  of  each  clavicle,  forms 
the  right  and  left  vense  innominatos  ; these  veins  enter  the  chest,  and  uniting, 
commence  the  superior  vena  cava,  as  will  be  seen  in  the  dissection  of  the 
thorax. — For  the  more  particular  description  of  the  vessels  of  the  neck,  see 
the  anatomy  of  the  vascular  system. 

The  gustatory  nerve  is  the  principal  branch  of  the  inferior  maxillary,  or 
third  division  of  the  fifth  pair;  it  is  seen  on  dividing  the  mylo-hyoid,  taking 
an  arched  course  parallel  to  the  stylo-glossus  muscle,  from  within  the  angle 
of  the  jaw  towards  the  tip  and  side  of  the  tongue;  it  accompanies  the  Whar- 
tonian  duct,  and  rises  above  the  sublingual  gland,  between  it  and  the  tongue ; 
it  gives  branches  to  the  submaxillary  and  sublingual  glands,  and  terminates 
in  fine  filaments,  which  are  lost  in  the  papillae  beneath  the  mucous  membrane, 
covering  the  sides  and  tip  of  the  tongue.  The  chorda  tympani  joins  it  near 
the  condyle  and  parts  from  it  opposite  the  angle  of  the  lower  maxilla ; this 
delicate  nerve  then  swells  into  a small  ganglion,  whose  branches  pass  into  the 
submaxillary  gland.  The  eighth  pair  of  nerves  leave  the  cranium  by  the 
foramen  lacerum  posterius,  anterior  to  the  jugular  vein  ; it  immediately  sepa- 
rates into  its  three  portions,  the  internal  or  glosso-pharvngeal,  the  external  or 
spinal  accessory,  and  the  middle  or  par  vagum.  The  glosso-pharyngeal, 
is  connected  to  the  stylo- pharyngeus  muscle,  its  name  denotes  its  destination ; 
the  arch  which  it  forms,  as  it  runs  to  the  base  of  the  tongue,  is  inferior  to  and 
deeper  in  the  neck  than  the  gustatory  nerve.  The  spinal  accessory  nerve 
separates  from  the  par  vagum,  and  in  general  winds  round  behind  the  internal 
jugular  vein,  perforates  the  sterno-mastoid  muscle,  as  was  before  mentioned, 
and  distributes  its  branches  to  it  and  to  the  trapezius;  several  of  these  also 
communicate  with  the  cervical  plexus,  and  descend  to  the  acromion.  The 
par  vagum,  or  pneumo- gastric  descends  along  the  neck,  between,  and  rather 
behind  the  carotid  artery  and  jugular  vein,  and  enclosed  in  their  sheath;  it 
then  passes  through  the  thorax,  and  terminates  on  the  stomach.  The  cervical 
portion  only  of  this  nerve  is  to  be  observed  at  present ; from  it  arise  several 
branches,  viz.  communicating  branches  to  join  the  sympathetic  and  lingual ; 
pharyngeal  branches  to  the  side  of  the  pharynx;  superior  laryngeal  nerve, 
which  takes  an  arched  course  behind  the  great  vessels  to  the  thyroid  cartilage, 
and  is  distributed  to  the  upper  part  of  the  larynx  ; and  small  cardiac  branches 
of  the  sympathetic  nerve.  At  the  inferior  part  of  the  neck,  ou  each  side 


OR  MANUAL  OF  ANATOMY. 


21 


of  the  trachea,  a large  nerve,  the  inferior  laryngeal  or  recurrent  nerve,  is  seen ; 
this  is  also  a branch  of  the  par  vagum.  On  the  right  side,  this  nerve  arises 
at  the  lower  part  of  the  neck,  turns  round  the  subclavian  artery,  and  passing 
behind  it  and  the  carotid,  pursues  its  course  upwards  and  inwards  behind  the 
thyroid  gland,  to  the  lower  and  back  part  of  the  larynx ; on  the  left  side  the 
recurrent  nerve  arises  in  the  thorax,  opposite  the  lower  part  of  the  arch  of  the 
aorta,  under  which  it  passes,  and  then  attaching  itself  to  the  forepart  of  the 
oesophagus,  ascends  to  the  larynx,  to  the  muscles  of  which  it  is  distributed 
like  that  of  the  opposite  side.  At  the  inferior  part  of  the  neck  the  eighth- 
pair  of  nerves  enter  the  thorax;  that  of  the  right  side  passes  anterior  to  the 
subclavian  artery,  crossing  it  at  a right  angle ; that  of  the  left  side  descends 
anterior  but  parallel  to  the  left  subclavian  artery.  The  ninth  pair,  or  lingual 
nerve,  leaves  the  cranium  by  the  anterior  condyloid  hole  in  the  occipital  bone, 
descends  forwards  and  inwards,  nearly  parallel  to  the  digastric  muscle,  and 
is  distributed  to  the  muscles  of  the  tongue : the  arch  which  the  course  of  this 
nerve  describes  is  parallel,  but  inferior  to  that  of  the  gustatory.  From  the 
convexity  of  this  arch  a long  branch  arises,  the  decendens  noni;  this  descends 
along  the  forepart  of  the  sheath  of  the  carotid  artery,  communicates  with 
the  second  and  third  cervical  nerves  about  the  middle  of  the  neck,  and  is 
distributed  to  the  sterno-hyoid  and  thyroid  muscles  : in  some  cases  this 
nerve  descends  within  the  sheath  behind  the  vein.  The  sympathetic  nerve 
may  be  found  descending  along  the  vertebrae  posterior  to  the  carotid 
artery:  this  nerve  commences  at  the  base  of  the  cranium  in  a long,  oval, 
red  swelling,  the  superior  cervical  ganglion,  which  extends  as  low  as  the 
third  cervical  vertebra;  from  this  the  nerve  becoming  very  small,  descends 
almost  vertically,  and  in  general  opposite  the  fifth  cervical  vertebra,  it 
forms  a second  swelling,  called  the  middle  cervical  ganglion;  from  this, 
the  small  nervous  cord  continues  its  course  down  the  neck,  and  opposite  the 
seventh  cervical  vertebra  and  the  neck  of  the  first  rib,  it  expands  into  a large 
irregular  swelling,  the  inferior  cervical  ganglion,  from  the  lower  part  of 
which  the  nerve  descends  into  the  thorax.  (For  the  particular  description  of 
the  branches  of  the  sympathetic,  as  well  as  of  the  cerebral  nerves,  met  with 
in  the  dissection  of  the  neck,  see  the  Anatomy  of  the  Nervous  System.)  On 
the  side  of  the  neck  are  seen  numerous  branches  of  the  cervical  spinal 
nerves;  there  are  eight  pair  of  cervical  nerves ; the  first,  or  suboccipital,  is 
very  small ; the  eighth  is  very  large ; the  first  leaves  the  spinal  canal  between 
the  occipital  bone  and  the  atlas ; and  the  eighth  between  the  last  cervical  and 
first  dorsal  vertebra:  these  cervical  nerves  all  divide  into  a posterior  and 
anterior  branch,  the  former  are  distributed  to  the  muscles  and  integuments 
on  the  back  of  the  neck ; the  anterior  branches  of  the  first,  second,  third,  and 
fourth,  communicate  with  each  other,  and  give  origin  to  several  branches, 
which  again  unite  with  each  other,  and  constitute  the  cervical  plexus ; this 
plexus  is  between  the  mastoid  and  trapezius  muscles;  it  sends  off  several 
branches,  which  are  entangled  with  much  cellular  membrane  and  several 
absorbent  glands ; the  anterior  branches  of  the  four  inferior  cervical  nerves 
with  that  of  the  first  dorsal,  unite  and  form  the  brachial  plexus ; this  is 
situated  at  the  lateral  and  inferior  part  of  the  neck,  and  accompanies  the 
subclavian  artery  beneath  the  clavicle  into  the  axilla,  in  which  region  the 
plexus  divides  into  several  branches  to  supply  the  upper  extremity  and  the 


22 


THE  DUBLIN  DISSECTOR, 


muscles  on  the  parietes  of  the  thorax.  In  the  inferior  and  lateral  part  of  the 
neck,  on  each  side,  the  phrenic  nerve  is  also  seen;  this  arises  by  several  fine 
filaments  from  the  third,  fourth,  fifth  cervical  nerves ; the  phrenic  nerve 
descends  obliquely  inwards  along  the  anterior  scalenus  muscle,  enters  the 
thorax  between  the  subclavian  vein  and  artery,  and  is  distributed  to  the 
diaphragm.  Previous  to  examining  the  deep  muscles  of  the  neck,  the  student 
should  study  the  anatomy  of  the  mouth,  pharynx,  and  larynx. 

§ 2 .—Dissection  of  the  Mouth,  Pharynx  and  Larynx. 

The  cavity  of  the  mouth  may  be  exposed  by  dividing  the  commissures  of 
the  lips  and  the  cheek  of  one  side,  and  removing  a small  portion  of  the  side 
of  the  lower  jaw;  draw  forward  the  tongue  with  a tenaculum,  and  cleanse 
the  parts  very  well.  The  mouth  is  bounded  anteriorly  by  the  lips,  superiorly 
by  the  hard  and  soft  palate,  laterally  by  the  cheeks,  interiorly  by  the  tongue, 
and  mucous  membrane  reflected  from  it  to  the  gums  ; posteriorly  it  communi- 
cates with  the  pharynx:  this  opening  is  named  the  isthmus  faucium;  it  is 
bounded  above  by  the  velum  and  uvula,  below  by  the  tongue,  and  on  each 
side  by  the  arches  of  the  palate.  The  anterior  part  of  the  palate,  or  hard 
palate,  is  formed  of  the  palate  plates  of  the  maxillary  and  palate  bones,  cov- 
ered by  mucous  membrane  and  glands ; the  posterior  part  of  the  palate,  or 
soft  palate,  or  velum  pendulum,  consists  of  a dense  aponeurosis,  and  of  several 
muscles  and  glands,  enclosed  in  mucous  membrane;  the  cheeks  are  formed 
of  mucous  membrane,  covered  by  the  buccinator  and  a quantity  of  fat: 
several  small  mucous  glands  lie  between  the  membrane  and  this  muscle,  and 
towards  the  upper  and  back  part  on  each  side  we  perceive  the  small  opening 
of  Steno’s  duct.  The  mouth  is  lined  throughout  by  mucous  membrane,  which 
is  continuous  with  the  cutis  on  the  lips,  and  extends  posteriorly  through  the 
pharynx,  whence  it  ascends  to  line  the  nares,  the  Eustachian  tube  and  tym- 
panum on  each  side,  and  descends  to  line  the  oesophagus  and  larynx ; as  it  i^ 
reflected  from  one  surface  to  another,  it  forms  folds  or  frsena,  as  between  the 
lips  and  alveoli,  and  beneath  the  tongue;  at  the  sides  of  the  fauces,  also,  it 
forms  two  semilunar  folds  on  each  side,  called  the  pillars  or  arches  of  the 
palate : these  folds  enclose  muscular  fibres,  which  we  shall  examine  after- 
wards. On  looking  into  the  mouth,  either  in  the  living  or  dead  subject,  the 
following  objects  strike  the  attention  ; interiorly  the  tongue  and  teeth  ; later- 
ally the  cheeks;  posteriorly  the  back  part  of  the  pharynx ; superiorly  the 
hard  and  soft  palate,  from  the  centre  of  the  latter,  the  uvula,  and  from  the 
sides,  the  pillars  or  arches  descending  to  the  tongue  and  pharynx;  in  the 
recess  between  these  pillars  on  each  side  the  tonsil  or  amygdala  is  also  seen  ; 
lastly,  if  the  tongue  be  drawn  forward,  the  epiglottis  comes  into  view. 

The  tongue  isof  a triangular  shape  ; its  base,  thick  and  broad,  is  connecter 
to  the  epiglottis  and  palate  by  mucous  membrane,  and  to  the  os  hyoides  and 
inferior  maxilla  by  muscles ; the  apex  is  thin  and  unattached;  that  portion 
between  it  and  the  base  is  named  the  body  of  the  tongue ; all  the  upper  sur- 
face, the  sides,  and  about  one  third  of  its  inferior  surface,  are  covered  by 
mucous  membrane,  which  is  very  rough  superiorly,  from  the  number  of  papilla? 
that  project  through  it;  anteriorly,  these  papillae  are  small,  conical,  and  con- 
nected with  the  terminations  of  the  nerves  of  taste ; posteriorly  they  are 


OR  MANUAL  OF  ANATOMY. 


£3 


large,  round,  lenticular , and  very  irregular ; these  are  small  glands  which 
open  on  the  mucous  surface  : near  the  epiglottis  these  glandular  papillae  are 
often  observed  to  have  a peculiar  arrangement,  like  the  letter  v,  the  concavity 
turned  forwards ; behind  the  apex  of  this  angle,  a deep  depression  (foramen 
coBcurn)  is  observable;  this  contains  some  mucous  follicles:  a superficial 
groove  runs  along  the  dorsum  of  the  tongue,  one  more  distinct  exists  along 
the  inferior  surface,  so  that  this  organ  is  divided  by  the  mesila  line  into  two 
symmetrical  portions  ; accordingly,  in  paralysis,  one  side  only  ot  this  organ  is 
frequently  found  affected,*  The  substance  of  the  tongue  is  composed  ot 
adeps  blended  with  numerous  muscular  fibres  derived  from  the  stylo,  hyo, 
genio-hyo-glossi,  and  linguales  muscles,  and  of  many  other  fleshy  fibres  which 
do  not  properly  belong  to  any  of  these : two  large  arteries  (lingual)  and  six 
considerable  nerves  (the  gustatory,  the  lingual  and  the  glosso-pharyngeal,  on 
each  side)  supply  this  organ.  The  tongue  is  not  only  the  organ  of  taste,  but 
by  its  great  mobility  it  assists  in  speech,  in  suction  and  deglutition ; the  fifth 
pair  of  nerves  endow  the  tongue  with  sensation  and  with  the  sense  of  taste, 
the  ninth  with  mobility,  and  the  eighth  connect  its  motions  with  those  of  the 
pharynx  and  stomach. 

§ 3. — Dissection  of  the  Pharynx. 

To  obtain  a view  of  the  muscles  of  the  pharynx  and  palate,  the  student 
may  now  make  the  following  dissection  ; divide  the  trachea  and  oesophagus  in 
the  lower  part  of  the  neck ; detach  them  from  the  vertebrae,  to  which  they  are 
loosely  connected  ; draw  forward  these  organs,  together  with  the  vessels  and 
nerves  on  either  side  ; place  the  saw  flat  on  the  bodies  of  the  vertebrae ; 
insinuate  its  edge,  between  the  styloid  and  mastoid  processes  on  each  side, 
and  make  a vertical  section  of  the  head ; we  have  thus  the  face  and  anterior 
part  of  the  cranium  separated  from  the  vertebral  column;  or,  should  it  be 
desirable  to  preserve  the  cranium,  we  may  separate  the  occipital  bone  from 
the  atlas,  and  then  remove  from  the  subject  the  whole  head,  together  with  the 
organs  we  wish  to  examine;  distend  the  pharynx  with  hair  or  tow,  and  remove 
some  of  the  loose  cellular  tissue  connected  to  it. 

The  pharynx  is  a large,  muscular,  and  membranous  bag,  extending  from  the 
base  of  the  cranium  to  the  fourth  or  fifth  cervical  vertebra,  where  it  ends  in 
the  oesophagus  ; it  is  placed  behind  the  nose,  mouth  and  larynx;  is  somewhat 
of  an  oval  form,  the  largest  part  being  opposite  the  os  h voides,  and  the  smaller 
extremity  joining  the  oesophagus.  The  pharynx  is  attached  superiorly  and 
posteriorly  to  the  cuneiform  process,  by  an  aponeurosis,  which  is  very  strong 
in  the  middle  line,  laterally  by  a thinner  aponeurosis  to  the  petrous  bone,  and 
anteriorly,  by  fleshy  fibres  to  the  internal  pterygoid  plate  and  hamular  process, 
and  to  the  posterior  part  of  the  mylo-hyoid  ridge  of  the  lower  maxilla; — the 
pharynx  is  connected  posteriorly  to  the  vertebra  and  to  the  deep  muscles  of; 
the  neck  by  loose  reticular  membrane ; anteriorly  it  is  attached  by  mucous 

* In  hemiplegia,  when  the  muscles  of  one  side  of  the  face  are  paralysed,  it  has  been  re- 
marked, that  if  the  tongue  be  protruded,  the  apex  will  be  directed  towards  the  affected  side, 
this  phenomenon,  which  is  only  an  apparent  exception,  depends  on  the  action  of  the  genio- 
hio-glossus  muscle  of  the  healthy  side ; which  will  pull  the  base  of  the  tongue  on  that  side, 
towards  the  chin,  and  must  therefore  turn  the  point  to  the  opposite  side. 


24 


THE  DUBLIN  DISSECTOR, 


membrane  and  muscular  fibres  to  the  cornua  of  the  os  hyoides  and  thyroid 
cartilage,  and  to  the  sides  of  the  cricoid,  behind  which  the  pharynx  abrupt]- 
contracts  and  ends  in  the  oesophagus ; on  either  side  of  the  pharynx,  and 
loosely  connected  to  it,  is  the  sheath  of  the  carotid  artery  with  its  accom- 
panying nerves.  The  muscular  fibres  which  cover  the  back  and  sides  of  the 
pharynx,  are  named  constrictor  muscles ; they  are  symmetrical,  and  overlap 
each  other ; the  inferior  being  most  superficial,  the  middle  next,  and  the 
superior  the  deepest ; the  constrictor  muscles  of  opposite  sides  have  one  com- 
mon insertion  into  the  middle  tendinous  line  or  raphe  on  the  back  part  of  the 
pharynx,  which  line  is  very  strong  and  distinct  superiorly,  being  inserted  into 
the  cuneiform  process,  but  interiorly  it  is  weak  and  often  indistinct. 

Constrictor  Pharyngis  Inferior  is  somewhat  square,  arises  from  the  side 
of  the  cricoid  cartilage,  from  the  inferior  cornu  and  posterior  part  of  the  ala 
of  the  thyroid  cartilage,  external  to  the  crico-thyroid  and  thyro-hyoid  ; the 
superior  fibres  ascend  obliquely,  and  overlap  the  middle  constrictor;  the  in- 
ferior fibres  run  circularly  and  overlap  the  (Esophagus  ; inserted  along  with 
that  of  the  opposite  side  into  the  middle  line  on  the  back  of  the  pharynx;  it- 
origin  is  covered  by  the  sterno-thyroid  muscle  and  the- thyroid  gland;  this 
muscle  lies  on  the  mucous  membrane,  except  its  superior  fibres,  which  are  sep- 
arated from  it  by  the  middle  constrictor.  The  inferior  laryngeal  nerve  passes 
beneath  its  lower  edge,  and  the  superior  laryngeal  beneath  its  upper. 

Constrictor  Pharyngis  Medius  is  of  a triangular  form,  arises  from  the 
cornu  and  appendix  of  the  os  hyoides,  also  from  the  stylo-hyoid  and  thyro- 
hyoid  ligaments  ; its  fibres  expand  on  the  back  of  the  pharynx,  the  superior 
ascend  to  the  occipital  bone,  the  middle  run  transversely,  and  the  inferior 
descend  beneath  the  lower  constrictor,  inserted,  into  the  mesial  tendinous 
line  or  raphe,  and  into  the  cuneiform  process.  The  lingual  artery  and  hyo- 
glossus  muscle  are  connected  to  the  origin  of  this  muscle,  which  part  is  sepa- 
rated from  the  inferior  constrictor  by  the  superior  laryngeal  nerve  and  cornu 
of  the  thyroid  cartilage,  and  from  the  superior  constrictor  by  the  stylo-pha- 
ryngeus muscle  and  glosso-pharyngeal  nerve ; on  dividing  the  edge  of  this 
muscle,  the  Stylo-pharyngeus  appears  ; it  arises  from  the  root  of  the  styloid 
process,  descends  to  the  side  of  the  pharynx,  where  it  expands  between  the 
superior  and  middle  constrictors,  and  is  inserted  partly  along  with  the  latter 
and  partl  y into  the  cornu  of  the  thyroid  cartilage.  Use,  to  elevate  and  dilate 
the  pharynx,  in  order  to  receive  the  food  from  the  tongue : divide  the  stylo- 
pharyngeus,  and  the  superior  constrictor  will  be  exposed. 

Constrictor  Pharyngis  Superior,  surrounds  the  superior  part  of  the 
pharynx ; arises  by  a dense  aponeurosis  from  the  petrous  bone,  which  soon 
becomes  connected  with  the  next  origin,  which  is  fleshy,  from  the  lower  pari 
of  the  internal  pterygoid  plate  and  hamular  process,  also  from  the  intermaxil- 
lary ligament  which  connects  it  to  the  buccinator  muscle,  from  the  posteri  i 
third  of  the  mylo-hyoid  ridge,  and  from  the  side  of  the  base  of  the  tongue  ; all 
the  fibres  take  a semicircular  course  backwards  and  inwards,  and  are  inserted 
into  the  cuneiform  process  and  into  the  middle  tendinous  line  on  the  back  of 
the  pharynx.  The  superior  constrictor  is  covered  by  the  styloid  muscles  and 
by  the  great  vessels  and  nerves,  and  interiorly  by  the  middle  constrictor,  from 
which  the  stylo-pharyngeus  and  glosso-pharyngeal  nerve  separate  it : between 
the  attachment  to  the  petrous  bone  and  that  to  the  occipital,  the  mucous 


OR  MANUAL  OF  ANATOMY. 


£5 


membrane  is  uncovered  by  muscular  fibres  in  a small  semicircular  space, 
named  sinus  of  Morgagni ; this  is  beneath  the  cuneiform  process,  on  each 
side  of  the  middle  line,  and  corresponds  to  the  Eustachian  tubes ; between  the 
temporal  and  pterygoid  attachments,  the  muscles  of  the  velum  lie,  and  between 
the  pterygoid  and  maxillary  origins  the  internal  pterygoid  muscle  and  the 
gustatory  nerve  are  situated.  Use,  the  constrictors  diminish  the  capacity  of 
the  pharynx,  and  by  the  successive  contractions  of  each,  the  food  is  forced 
into  the  oesophagus;  the  complex  muscular  structure  of  the  pharynx  may  also 
assist  in  the  modulation  of  the  voice  and  in  the  production  of  certain  sounds. 
Open  the  pharynx  by  a perpendicular  incision  through  the  middle  tendinous 
line;  on  looking  into  the  cavity  it  will  be  found  divided  by  the  velum  into 
two  portions,  a superior  and  inferior : seven  openings  also  may  be  remarked 
leading  from  it  in  different  directions,  viz.  in  the  upper  or  nasal  portion  there 
are  the  two  posterior  nares,  and  on  the  side  of  each  of  these  is  the  opening  of 
the  Eustachian  tube ; below  the  velum  is  the  isthmus  faucium,  or  posterior 
opening  of  the  mouth ; below  and  behind  the  tongue  is  the  opening  of  the 
glottis ; and  lastly,  the  termination  of  the  pharynx  in  the  oesophagus.  The 
opening  of  the  nares  are  of  an  oval  shape,  their  long  diameter  being  vertical; 
the  body  of  the  sphenoid  bone  bounds  them  superiorly,  the  palate  bones  inte- 
riorly, the  internal  pterygoid  plates  externally,  and  the  vomer  separates  them 
from  each  other:  through  these  openings  the  air  generally  passes  during 
respiration.  The  Eustachian  tube  open  on  each  side  of  the  posterior  nares, 
behind  the  inferior  spongy  bone ; they  are  circular,  and  look  forwards  and 
inwards  towards  the  septum  narium,  are  formed  of  thick  cartilage,  covered  by 
mucous  membrane;  through  these  air  is  admitted  from  the  nose  into  the 
tympanum,  to  support  the  membrana  tympani  on  its  inner  side.  The  Eusta- 
chian tube  must  be  again  examined  in  the  dissection  of  the  organ  of  hearing.* 
Beneath  the  velum  is  the  isthmus  faucium,  transversely  oval,  but  capable  of 
great  change  in  figure  and  size,  bounded  above  by  the  velum  and  uvula,  below 
by  the  tongue,  and  on  either  side  by  the  pillars  or  arches  of  the  palate,  and  by 
the  amygdalae.  The  opening  of  the  glottis,  or  superior  opening  of  the  larynx, 
is  at  the  lower  and  anterior  part  of  the  pharynx,  behind  the  epiglottis,  and 
rather  beneath  the  tongue  ; it  is  of  a triangular  form,  the  base  anteriorly, 
formed  by  the  epiglottis  ; the  sides  are  composed  of  folds  of  mucous  membrane, 
termed  aryteno-epiglottidean,  and  the  apex,  which  is  posteriorly,  is  formed  by 
the  appendices  of  the  arytenoid  cartilages.  The  glottis,  which  will  again  be 
considered  in  speaking  of  the  larynx,  is  always  open,  except  in  the  act  of  de- 
glutition. The  oesophageal  opening  is  below  and  behind  the  glottis ; it  is 
always  closed,  except  in  deglutition.  The  student  should  next  examine  the 
velum  pendulum  palati,  or  palatum  molle. 

§ 4. — Dissection  of  the  Palate  and  its  Muscles. 

TuEvelum  pendulum  palati  is  a.  soft  moveable  substance,  attached  supe- 
riorly and  anteriorly  to  the  hard  palate  on  each  side  of  the  tongue  and  pharynx, 

* The  student  may  practise  the  introduction  of  a probe  into  this  tube  ; slightly  curve  a blunt 
probe,  pass  it  along  the  floor  of  the  nose  to  the  posterior  nares,  then  direct  its  extremity  up- 
wards, outwards,  and  backwards,  that  is  toward  the  ear,  and  it  will  enter  this  tube. 


4 


26 


THE  DUBLIN  DISSECTOR, 


and  posteriorly  and  inferiorlyit  terminates  in  a thin  edge,  from  the  centre  of 
which  the  uvula  descends,  thus  giving  a lunated  appearance  to  the  edge  of  the 
velum  on  each  side ; these  crescentic  edges  are  named  the  half  arches  of  the 
palate.  The  velum  is  situated  obliquely,  its  fixed  edge  being  superior  and 
anterior  to  the  loose,  one  surface  looking  forwards  and  downwards  towards 
the  mouth  and  tongue,  the  opposite  surface  looking  upwards  and  backwards; 
during  life  this  aspect  can  be  altered  by  the  action  of  muscles,  which  can  either 
elevate,  depress,  or  make  tense  the  velum.  Beneath  the  mucous  membrane 
of  the  velum  several  small  glands  are  situated,  chiefly  on  the  inferior  surface. 
The  uvula  is  a conical  prolongation  of  the  velum,  enclosing  small  glands,  loose 
cellular  membrane,  and  some  muscular  fibres;  in  deglutition,  the  velum  and 
uvula  are  raised  so  as  to  touch  the  back  part  of  the  pharynx,  and  thus  they 
are  of  use  in  preventing  the  food  ascending  into  the  upper  or  nasal  part  of  the 
cavity,  from  which  it  might  regurgitate  into  the  nares.  The  muscles  of  the 
velum  are  five  pair,  the  levator  and  tensor  palati,  the  motor  uvulae,  palato 
glossus  and  palato-pharyngeus. 

Levator-Palati,  arises  narrow  from  the  petrous  bone,  in  front  of  the  fora- 
men caroticum  and  behind  the  Eustachian  tube,  descends  obliquely  inwards, 
and  is  inserted  broad  into  the  velum ; its  name  denotes  its  use. 

Tensor-Palati  vel  circumflexus  palati,  arises  fleshy  from  a depression  at 
the  root  of  the  internal  pterygoid  plate,  from  the  spinous  process  of  the  sphe- 
noid, and  from  the  forepart  of  the  Eustachian  tube,  descends  between  the 
internal  pterygoid  plate  and  muscle,  ends  in  a flat  tendon,  which  turns  round 
the  hamular  process  inwards  to  the  velum,  it  then  expands,  and  joins  that 
from  the  opposite  side.  Use , to  make  tense  the  velum  in  a horizontal  direc- 
tion between  the  hamular  processes. 

Motor  Uvulae,  arises  from  the  posterior  extremity  or  spine  of  the  palate 
bones,  descends  close  to  its  fellow,  along  the  median  line  of  the  velum,  and  is 
inserted  into  the  cellular  tissue  of  the  uvula.  Use,  to  raise  and  shorten  the 
uvula:  this  pair  of  muscles  are  so  close  that  they  appear  but  as  one,  hence 
they  have  sometimes  received  the  name  of  azygos  uvulae. 

Palato-Glossus  vel  constrictor  isthmi  faucium,  or  the  anterior  arch  or 
pillar  of  the  palate,  arises  from  the  inferior  surface  of  the  velum,  descends 
forwards  and  outw'ards,  enclosed  in  a fold  of  mucous  membrane  anterior  to 
the  tonsil.  Inserted  into  the  side  of  the  tongue.  Use,  to  elevate  the  tongue 
or  to  depress  the  velum,  this  pair  of  muscles  may  close  the  fauces. 

Palato-Piiaryngeus,  or  posterior  arch  of  the  palate,  arises  broad  from  the 
inferior  surface  of  the  palate,  arches  downwards  and  backwards  behind  the 
tonsil,  and  is  inserted  into  the  side  and  back  of  the  pharynx,  and  into  the  cornu 
of  the  thyroid  cartilage,  its  fibres  mixing  with  those  of  the  stylo-pharyngeus. 
Use,  to  elevate  the  pharynx,  like  the  stylo-pharyngei  in  the  commencement  of 
deglutition  ; but  afterwards  to  depress  the  velum. 

The  tonsil  or  amygdala  is  a congeries  of  mucous  glands,  of  an  irregular 
figure,  somewhat  oval,  the  larger  extremity  above,  placed  in  a triangular 
recess  between  the  pillars  of  the  palate,  above  the  side  of  the  base  of  the 
tongue,  covered  internally  by  the  mucous  membrane,  externally  by  the  supe- 
rior constrictor ; small  holes  are  remarked  on  its  surface  ; these  lead  into  cells 
from  which  the  mucus  can  be  expressed ; the  amygdalae  are  very  vascular  and 


OR  MANUAL  OF  ANATOMY. 


2 7 


secrete  a viscid  fluid,  which  being  pressed  out  in  the  moment  of  deglutitmnby 
the  contraction  of  the  surrounding  muscles,  serves  to  lubricate  the  alimentary 
bolus  in  its  passage. 

The  oesophagus  appears  as  the  continuation  of  the  pharynx,  it  differs  from 
it  however  in  structure  ; the  mucous  membrane  is  paler ; the  muscular  fibres 
are  arranged  in  two  laminae,  the  external  are  longitudinal,  strong  and  red, 
attached  superiorly  and  anteriorly  to  the  cricoid  cartilage,  and  below  are  lost 
on  the  stomach  ; the  internal  circular  fibres  are  pale,  and  cease  abruptly  atthe 
cardiac  orifice  of  the  stomach.  In  the  neck  the  oesophagus  descends  posterior 
to  the  trachea,  and  nearly  in  the  middle  line ; it  inclines  a little  to  the  left  side 
below,  so  as  to  be  uncovered  by  that  tube ; the  left  lobe  of  the  thyroid  gland,  the 
recurrent  nerve,  and  the  inferior  thyroid  vessels,  lie  on  it  in  this  situation.  The 
course  and  connections  of  the  oesophagus  in  the  chest  will  be  seen  hereafter.* 

§ 5. — Dissection  of  the  Larynx. 

The  larynx  is  composed  of  several  cartilages  and  muscles;  it  is  placed  at 
the  anterior  part  of  the  neck,  between  the  tongue  and  the  trachea,  and  in  front 
of  the  pharynx  and  oesophagus,  it  is  suspended  by  muscles  and  ligaments  from 
the  os  hyoides  ; this  bone  is  connected  to  the  chin  by  several  muscles,  and  to 
the  styloid  process  of  the  temporal  bone  on  each  side  by  the  digastric  and 
stylo-hyoid  muscle  and  ligament ; it  consists  of  five  parts,  the  middle  portion, 
or  body,  is  very  rough  and  convex  anteriorly  for  the  attachment  of  muscles, 
concave  posteriorly  where  it  covers  the  epiglottidean  gland  ; from  the  body 
the  cornua  pass  off,  one  to  either  side,  giving  attachment  to  muscles  above  and 
below,  lined  by  mucous  membrane,  and  serving  to  expand  the  pharynx  and 
fauces;  where  each  cornu  joins  the  body,  a small  process,  the  appendix  ascends 
obliquely  backwards,  and  gives  attachment  to  the  stylo-hyoid  ligament  and 
musde.  Use,  to  serve  as  a fixed  point  for  the  muscles  of  the  tongue,  pharynx 
and  larynx. 

Four  cartilages  enter  into  the  formation  of  the  skeleton  of  the  larynx,  the 
thyroid,  cricoid  and  two  arytenoid,  and  one  fibro-cartilage,  the  epiglottis. 
The  thyroid-cartilage  is  placed  at  the  anterior  and  lateral  parts  of  the  larynx ; 
it  presents,  anteriorly,  a prominence,  named  in  the  male  subject,  the  pomum 
did  a mi,  laterally  the  alse,  each  of  which  in  passing  backwards,  increases  in 
depth,  and  presents  an  oblique  ridge  for  the  attachment  of  the  sterno-thyroid, 

*■  The  student  should  practise  the  passing  of  a probe  or  canula  armed  with  a ligature,  along 
the  nares  into  the  pharynx,  and  endeavor  to  enclose  the  uvula  in  the  noose,  thus  imitating  the 
operation  of  tying  polypi  when  situated  in  the  pharynx,  on  the  velum,  or  in  the  posterior  nares  : 
he  may  also  pass  a flexible  tube  into  the  pharynx,  and  thence  direct  it  to  the  stomach  or  into 
the  larynx  ; any  practitioner  may  be  suddenly  called  on  to  use  the  stomach  pump  in  case  of 
poison  having  been  swallowed,  or  to  inflate  the  lungs  in  asphyxia  : in  the  first  case  when  the 
tube  has  been  passed  into  the  pharynx,  from  the  mouth  or  nares,  the  tongue  should  be  pressed 
bade,  so  as  to  close  the  glottis,  and  the  end  of  the  instrument  should  be  kept  close  to  the  ver- 
tebra to  avoid  irritating  or  pressing  on  the  epiglottis  : in  the  second  case,  the  tube  should  be 
passed  through  either  naris  into  (he  pharynx,  tire  forceps  or  the  finger  of  the  surgeon  intro- 
duced into  the  mouth,  can'then  guide  it  downwards  and  forwards  to  the  glottis;  at  this  time, 
however,  the  tongue  should  be  drawn  forwards ; thus  the  epiglottis  will  be  raised  and  the 
glottis  opened  opposite  the  edge  of  the  velum ; the  tube  may  then  be  urged  into  the  larynx, 
and  artificial  respiration  commenced:  in  conducting  this  process  it  is  advisable  to  press  the  upper 
part  of  the  trachea  gently  against  the  vertebrae,  so  as  to  fix  the  larynx  and  the  tube,  as  well  as 
to  guard  against  the  admission  of  air  into  the  oesophagus,  and  the  consequent  inflation  of  the 
stomach. 


28 


THE  DUBLIN  DISSECTOR, 


and  thyro-hyoid  muscles  ; a hole  is  frequently  observed  in  each  ala  near  this 
ridge ; posteriorly  the  aim  terminate  round  and  thick,  and  from  their  upper 
and  lower  extremity  send  off  the  processes  called  cornua ; the  ascending 
cornua  are  connected  to  the  cornua  of  the  os  hyoides  by  round  ligaments, 
which  are  often  cartilaginous,  and  even  bony ; the  inferior  cornua  are 
shorter,  and  are  attached  by  synovial  membranes  and  capsular  ligaments  to 
the  sides  of  the  cricoid  cartilage  ; the  anterior  angle  of  the  thyroid  is  con- 
nected superiorly  to  the  body  of  the  os  hyoides  by  a thin  membrane,  anterior 
hyo-thyroid  ligament , and  inferiorly  to  the  cricoid  cartilage  by  a strong 
elastic  ligament,  crico-thyroid. — The  cricoid , or  annular  cartilage,  forms 
the  lower  part  of  the  larynx,  is  narrow  before,  deep  behind ; the  inferior  edge 
or  circumference  is  nearly  horizontal ; the  superior  is  oblique,  leading  from 
above  and  from  behind,  downwards  and  forwards;  on  its  posterior  surface  is 
a middle  prominent  ridge,  on  each  side  of  which  is  a depression,  filled  by  the 
posterior  crico-arytenoid  muscle  ; at  the  upper  and  back  part  on  each  side 
is  a smooth  articulating  convex  surface,  on  which  arytenoid  cartilage  moves. 
— The  arytenoid  cartilages  are  triangular,  the  base  below  moving  on  the  cri- 
coid, the  apex  above  inclining  a little  backwards,  and  surmounted  by  a small 
process,  the  appendix ; the  internal,  or  opposed  side  of  each  cartilage  is  flat, 
the  external  is  rough  for  the  insertion  of  muscles,  the  posterior  surface  of 
each  is  concave,  and  covered  by  the  arytenoid  muscle;  the  anterior  is  sharp, 
and  connected  superiorly  to  the  epiglottis  by  the  aryteno-epiglottidean  folds 
of  mucous  membrane,  which  folds  form  the  sides  of  the  glottis,  and  inferiorly 
to  the  angle  of  the  thyroid  by  two  ligaments  on  each  side,  called  thyro-ary- 
tenoid,  or,  chordae  vocales ; these  arise  from  a sharp  projection  on  the  fore 
part  of  the  base  of  each  arytenoid,  pass  forwards  converging,  and  are  inserted 
into  the  angle  of  the  thyroid;  the  inferior  is  tendinous  and  horizontal,  the 
superior  membranous  and  semilunar:  the  narrow  passage  between  these  lig- 
aments of  opposite  sides  is  called  the  rima  g/ottidis;  between  the  superior 
and  inferior  ligament  of  each  side  is  a semilunar  fossa  called  the  sinus  or 
ventricle  of  the  larynx.  The  epiglottis,  or  fibro-cartilage,  is  anterior  to 
the  glottis;  it  is  somewhat  of  an  oval  form,  connected  inferiorly  by  a stalk- 
like process  to  the  angle  of  the  thyroid;  anteriorly  by  cellular  membrane  and 
by  the  epiglottidean  gland  to  the  os  hyoides,  also  to  the  tongue  by  three  folds 
of  mucous  membrane,  the  central  one  of  which  is  called  the  fraenum  epiglot- 
tidis;  posteriorly  to  the  arytenoid  cartilages  by  the  folds  of  mucous  mem- 
brane, which  form  the  sides  of  the  glottis.  The  epiglottis  stands  nearly 
vertical ; it  is  a little  curved  forwards  at  its  upper  border  and  along  its  sides, 
so  that  its  anterior  surface  is  concave  from  above  downwards,  and  convex 
transversely ; and  its  posterior  surface  is  concave  from  side  to  side,  and 
convex  from  above  downwards;  it  is  very  elastic,  and  never  found  ossified,  a 
change  which  the  cartilages  of  the  larynx  are  prone  to  undergo:  in  degluti- 
tion the  epiglottis  is  of  much  use ; it  covers  the  larynx,  and  so  prevents  any 
foreign  substance  entering  it : during  this  act  the  tongue  is  turned  backwards, 
and  the  larynx  raised  forwards;  thus  the  glottis  is  closed,  and  the  contents 
of  the  mouth  pass  over  the  epiglottis  into  the  pharynx.  The  larynx  is  lined 
by  mucous  membrane,  which  passing  from  the  tongue  and  pharynx,  covers 
the  epiglottis  and  arytenoid  cartilages,  forms  their  connecting  folds,  descends 
into  the  larynx,  covers  the  chordae  vocales,  lines  the  ventricles  of  the  larynx 


OR  MANUAL  OF  ANATOMY. 


29 


and  is  continued  down  through  the  trachea  and  the  branches  of  that  tube  ; it 
is  but  loosely  connected  to  the  cartilages  above  at  the  glottis,  but  more  closely 
below ; several  mucous  glands  are  connected  to  it,  thus  in  the  aryteno-epiglot- 
tidean  fold  of  each  side  there  are  small  glands  called  arytenoid,  and  in  front 
of  the  epiglottis,  behind  the  os  hyoirles,  the  epiglottidean  gland  is  situated  ; 
this  opens  by  small  ducts  on  the  posterior  or  laryngeal  surface  of  the  epiglottis. 
The  openings  of  the  larynx  are  two,  the  superior  or  the  glottis,  and  the  in- 
ferior, or  the  rima  glottidis.  The  opening  of  the  glottis  has  been  already 
noticed ; it  is  immediately  behind  the  tongue  and  epiglottis,  and  is  of  a tri- 
angular form,  the  base  anteriorly.  The  rima  glottidis  is  three  quarters  of  an 
inch  below  the  glottis ; it  is  like  a slit,  being  very  narrow  from  side  to  side, 
and  of  a triangular  figure,  the  base  posteriorly  formed  by  the  bases  of  the 
arytenoid,  and  by  the  upper  and  posterior  edge  of  the  cricoid ; the  apex  is 
anteriorly  in  the  angle  of  the  thyroid  cartilage,  the  chordae  vocales  form  the 
sides : below  the  rima  glottidis  the  larynx  enlarges  within  the  cricoid  car- 
tilage, and  is  of  a circular  figure,  and  soon  terminates  in  the  trachea.  The 
muscles  of  the  larynx  are  symmetrical,  they  are  found  on  the  front,  sides,  and 
back  part;  those  on  the  fore  part  are  the  thyro-hyoid,  and  crico-thyroid  ; on 
each  side  are  the  thyro  and  lateral  crico-arytenoid,  and  posteriorly  are  the 
arytenoid  and  posterior  crico-arytenoid. 

Thyro-hyoidetjs,  broad  and  flat,  arises  from  the  oblique  ridge  on  the  ala 
of  the  thyroid  cartilage,  ascends  a little  outwards,  and  is  inserted  into  the 
lower  edge  of  the  cornu  of  the  os  hyoides.  Use,  to  elevate  and  draw  forwards 
the  larynx  beneath  the  tongue  and  epiglottis,  and  so  cause  the  glottis  to  be 
closed  in  deglutition.  This  muscle  is  partly  covered  by  the  integuments  and 
sterno-hyoid  ; it  appears  like  a continuation  of  the  sterno-thyroid. 

Crico-thyroideus,  inferior  to  the  former,  short  and  triangular : arises 
narrow  from  the  forepart  of  the  cricoid  cartilage,  ascends  obliquely  outwards 
and  is  inserted  broad  into  the  lower  border  of  the  thyroid.  Use,  to  approxi- 
mate these  cartilages,  and  to  draw  forward  the  cricoid.  The  crico-thyroid 
ligament  occupies  the  space  between  these  muscles  ; they  are  covered  by  the 
sterno-hyoid.  Raise  the  ala  of  the  thyroid  cartilage  on  one  side,  and  the 
lateral  muscles  of  the  larynx  will  be  exposed. 

Thyro-arytenoideus,  is  fiat  and  thin,  arises  from  the  posterior  surface  of 
the  thyroid  cartilage  near  its  angle : the  fibres  pass  backwards  and  outwards, 
expanding  over  the  side  of  the  rima  glottidis,  and  are  inserted  into  the  ante- 
rior edge  of  the  arytenoid  cartilage.  Use,  to  draw  the  cartilage  forwards  and 
towards  its  fellow,  thereby  diminishing  the  capacity  of  the  rima  glottidis ; 
these  muscles  can  also  produce  various  alterations  in  the  form,  position,  and 
degree  of  tension  of  the  chordae  vocales,  which  they  cover,  and  they  can 
compress  the  sinus,  or  sacculus  laryngis.  The  thyro-arytenoid  muscles  are 
considered  by  some  as  the  principal  and  most  important  agents  in  the  pro- 
duction of  voice,  in  consequence  of  their  proximity  to  the  vocal  chords,  and 
their  capability  of  producing  endless  varieties  in  their  condition,  causing  the 
vibration  in  their  edges  so  to  differ  in  intensity  and  duration,  as  to  produce, 
from  the  air  passing  over  them,  (to  a certain  extent  only)  corresponding 
varieties  of  sound  or  tone. 

These  muscles  are  covered  by  the  alae  of  the  thyroid  cartilage  ; they  lie  on 
the  chordae  vocales,  and  the  intermediate  sinus ; superiorly,  their  fibres  extend 


so 


THE  DUBLIN  DISSECTOR, 


to  an  indefinite  height  in  the  mucous  folds  of  the  glottis,  and  inferiorly  they 
are  connected  to  the  following  muscles. 

Crico-arytenoideus  lateralis,  arises  from  the  upper  edge  of  the  side  of 
the  cricoid  cartilage ; ascends  obliquely  backwards,  inserted  into  the  base  of 
the  arytenoid.  Use , to  draw  that  cartilage  forwards  and  outwards,  and  thus 
to  relax  the  vocal  chords,  and  enlarge  the  rima  from  side  to  side,  but  contract 
it  from  before  backwards.  Raise  the  mucous  membrane  on  the  back  part  of 
the  larynx,  to  expose  the  muscles  situated  there. 

Crico-arytenoideus  Posticus,  strong  and  flat,  arises  from  the  depression 
on  the  posterior  surface  of  the  cricoid  ; the  fibres  ascend  obliquely  outwards, 
inserted  by  a tendon  into  the  outside  of  the  base  of  the  aryteniod  cartilage. 
Use,  to  draw  this  cartilage  backwards  and  outwards,  so  as  to  enlarge  the  rima 
in  every  direction,  as  in  full  inspiration.  These  muscles  lie  on  the  back  of 
the  cricoid  cartilage,  and  are  covered  posteriorly  by  the  pale  mucous  mem- 
brane descending  into  the  oesophagus : these  and  the  crico-thyroid  muscles 
are  the  dilators  of  the  rima  glottidis. 

Arytenoideus,  fills  the  interval  between  the  arytenoid  cartilages,  and  is 
enclosed  in  a fold  of  mucous  membrane:  it  consists  of  oblique  and  transverse 
fibres ; the  former  consist  of  two  or  three  fasciculi,  which  pass  from  the  apex 
of  one  cartilage  to  the  base  of  the  opposite ; the  transverse  fibres  are  more 
numerous,  and  are  attached  to  the  posterior  surface  of  each  cartilage.  Use,  to 
approximate  these  cartilages,  and  close  the  sides  of  the  rima : these,  together 
with  the  thyro  and  crico-arytenoidei  laterals  are  the  contractors  of  the  rima 
glottis.  In  the  aryteno-epiglottidean  folds,  fleshy  fibres  are  sometimes  dis- 
cernible, and  have  been  described  as  distinct  muscles,  and  named  from  their 
situation,  aryteno-epiglottidean  and  thyreo-epiglottideun  or  the  depressors 
of  the  epiglottis.  In  the  human  subject,  however,  these  are  never  sufficiently 
Well  marked  to  merit  the  appellation  of  distinct  muscles. 

The  arteries  which  supply  the  larynx  are  derived  from  the  superior  and  in- 
ferior thyroid  ; the  former  is  a branch  of  the  external  carotid,  the  latter  of  the 
subclavian.  The  laryngeal  nerves  are  four  in  number,  two  on  each  side,  the 
superior  and  inferior ,-  both  are  derived  from  the  par  vagum  or  pneumo-gas- 
tric  ; the  former  arising  from  it  near  the  base  of  the  cranium,  the  latter,  on  the 
right  side,  comes  off  from  this  trunk  at  the  lower  part  of  the  neck,  and  on  the 
left  side  it  arises  from  it  in  the  thorax,  below  the  arch  of  the  aorta : the  inferior 
laryngeal  nerves  are  principally  distributed  to  the  muscles,  and  the  superior 
to  the  membrane  and  glands  of  the  larynx,  but  not  exclusively  so. 

The  inferior  supply  the  posterior  and  lateral  crico-arytenoid  and  the  thyro- 
arytenoid muscles ; the  superior  sends  a large  branch  to  the  arytenoid,  and  a 
small,  but  very  long  filament  to  the  crico-thyroid  muscle  ; several  branches  of 
this  nerve  are  distributed  to  the  epiglottis,  and  to  the  mucous  membrane  at 
the  glottis,  which  in  this  situation  possesses  great  sensibility. 

§ 6. — Dissection  of  the  deep  muscles  of  the  neck. 

These  muscles  lie  close  to  the  vertebrae,  and  are  exposed  by  removing  the 
pharynx,  larynx,  cervical  vessels  and  nerves. 

Longus  Colli  extends  from  the  third  dorsal  vertebra  to  the  atlas  ; it  arises 
from  the  bodies  of  three  superior  dorsal  and  four  inferior  cervical  vertebrae, 


OR  MANUAL  OF  ANATOMY. 


31 


from  the  intervertebral  ligaments,  also  from  the  head  of  the  first  rib,  and  from 
the  anterior  tubercles  of  the  transverse  processes  of  the  four  last  cervical  ver- 
tebrae ; the  fibres  ascend  obliquely  inwards,  adhering  to  each  bone  in  their 
course,  and  are  inserted  into  the  forepart  of  the  1st,  2d  and  3d  cervical  verte- 
brae. Use,  to  bend  the  neck  to  one  side,  and  rotate  the  atlas  on  the  dentatus; 
or,  if  both  muscles  act,  to  bend  the  neck  directly  forwards.  This  muscles 
appears  to  consist  of  an  inferior  and  superior  portion ; the  first  arising  from 
the  bodies  of  the  dorsal  is  inserted  into  those  of  the  inferior  cervical  vertebrae 
the  second  arising  from  the  transverse  processes  of  the  3d,  4th  and  5th  cervical 
vertebrae,  is  inserted  into  the  bodies  of  the  1st  and  2d.  These  muscles,  like 
most  of  those  which  adhere  to  the  vertebrae,  though  long,  yet  consist  of  short 
fibres  which  pass  from  one  bone  to  another,  are  generally  intermixed  with  ten- 
dinous substance,  and  are  irregular  as  to  the  number  of  the  vertebrae  to  which 
they  are  attached. 

Rectus  Capitis  Anticus  Major,  long  and  flat,  arises  by  small  tendons  from 
the  anterior  tubercles  of  the  transverse  processes  of  the  four  last  cervical  verte- 
brae ; they  soon  unite  in  a fleshy  substance  which  ascends  obliquely  inwards 
and  is  inserted  broad  into  the  cuneiform  process.  Use,  to  bend  forwards  the 
neck  and  head.  This  muscle  lies  behind  the  carotid  artery  and  sympathetic 
nerve,  and  between  the  longus  colli  and  scaleni.  Separate  this  muscle  from  its 
insertion,  and  we  expose  the  following : 

Rectus  Capitis  Anticus  Minor,  short  and  narrow,  anses  from  the  transverse 
process  of  the  atlas,  ascends  inwards,  and  is  inserted  into  the  cuneiform  pro- 
cess. Use,  to  bend  the  head  forwards  and  to  one  side  on  the  atlas  : this  muscle 
lies  to  the  outer  side,  but  is  in  part  concealed  by  the  last. 

Rectus  Capitis  Lateralis,  very  short,  arises  from  the  transverse  pro- 
cess of  the  atlas,  ascends,  and  is  inserted  into  the  semilunar  ridge  or  jugu- 
lar process  of  the  occipital  bone.  Use,  with  the  last  muscle  it  can  bend  the 
head  forwards  or  incline  it  to  one  side.  This  muscle  is  external  to  that  last 
described;  it  lies  on  the  vertebral  artery,  and  is  covered  by  the  jugular 
vein. 

Scalenus  Anticus,  arises  tendinous  from  the  anterior  tubercles  of  the 
transverse  processes  of  the  3d,  4th,  5th  and  6th  cervical  vertebrae  ; the  fibres 
descend  obliquely  forwards  and  outwards,  from  a flat  muscle,  which  is  insert- 
ed tendinous  into  the  upper  surface  of  the  first  rib,  near  its  cartilage.  Use, 
to  bend  the  neck  forwards  and  laterally,  also  to  elevate  and  fix  the  rib  as 
in  inspiration.  The  phrenic  nerve  decends  on  the  anterior  surface  of  this 
muscle ; the  subclavian  vein  crosses  its  insertion  ; the  omo-hyoid  and  st’erno- 
mastoid  lie  anterior  to  it ; the  subclavian  artery  and  brachial  plexus  are  behind 
it,  and  the  vertebral  vessels  separate  it  from  the  longus  colli. 

Scalenus  Medius,  arises  from  the  posterior  tubercles  of  the  transverse  pro- 
cesses of  four  or  five  inferior  cervical  vertebrae,  by  small  tendinous  fibres  ; 
these  become  fleshy,  anddescendobliquely  outwards  and  backwards,  and  are 
inserted  into  the  upper  surface  of  the  second  rib  behind  the  subclavian  artery. 
Use,  similar  to  the  last.  This  muscle  is  covered  by  the  brachial  plexus,  sub- 
clavian artery,  and  anterior  scalenus. 

Scalenus  Posticus,  arises  from  the  posterior  tubercles  of  two  or  three  lower 
cervical  vertebrae,  descends  behind  the  former,  and  is  inserted  into  the  upper 
edge  of  the  second  rib,  between  its  tubercle  and  angle.  Use,  to  elevate  the 


32 


THE  DUBLIN  DISSECTOR, 


second  rib,  to  bend  the  neck  to  one  side,  and  a little  backwards.  One  or  two 
branches  of  the  brachial  plexus  sometimes  separate  this  from  the  middle 
scalenus,  at  other  times  there  is  no  distinction  between  them,  excepting  in 
their  insertion ; behind  the  posterior  scalenus  lie  the  transversalis  and  splenius 
colli,  also  the  levator  anguli  scapulae,  which  muscles  cannot  be  examined  at 
present.  We  shall  next  proceed  to  the  dissection  of  the  thorax. 


CHAPTER.  III. 

DISSECTION  OF  THE  THORAX. 

§ 1. — Of  the  muscles  on  the  anterior  and  lateral  parts  of  the  Thorax. 

Make  one  incision  through  the  integuments  along  the  clavicle,  a second 
from  the  upper  end  of  the  sternum  to  the  ensiform  cartilage,  and  from  this 
point  carry  a third  towards  .the  shoulder ; reflect  the  integuments  and  sub- 
jacent cellular  membrane  from  within  and  from  below,  upwards  and  outwards, 
and  thus  the  great  pectoral  muscle  will  be  exposed,  the  dissection  of  which 
will  be  facilitated  if  its  fibres  be  made  tense  by  separating  the  arm  from  the 
side.  Beneath  the  integuments  in  the  female  we  find  the  mammary  gland  ; 
this  is  a conglomerate  gland,  imbedded  in  fat,  hemispherical,  flat  posteriorly, 
convex  anteriorly,  surrounded  by  a capsule  of  condensed  cellular  membrane, 
which  is  loosely  connected  to  the  pectoral  muscle,  and  sends  processes  into 
the  gland  to  support  and  connect  its  several  lobules;  these  last  are  very  soft 
and  pale,  almost  white ; from  each  of  them  small  ducts  arise,  which  uniting 
together  form  larger  tubes ; these  converge  towards  the  root  of  the  nipple, 
where  they  expand  into  sinuses,  from  which  smaller  ducts  proceed  and  open 
on  its  surface  : the  skin  covering  the  breast  is  soft  and  delicate,  and  about  the 
centre  of  it,  is  the  conical  projection  called  the  nipple,  near  the  point  of  which 
the  lactiferous  ducts  open ; the  base  is  surrounded  by  an  areola  of  a dark  co- 
lor. This  gland  will  be  found  tn  differ  in  structure  in  different  subjects  ; in 
some  the  capsule  is  indistinct,  and  the  lobules  scattered,  or  more  separate 
than  usual;  in  some  it  has  a redder  appearance  than  in  others,  and  it  fre- 
quently feels  unusually  hard  or  rugged,  although  free  from  disease. 

Pectoralis  Major,  flat  and  triangular,  arises  somewhat  tendinous  from 
the  sternal  half  of  the  clavicle,  from  the  anterior  surface  of  the  sternum, 
fleshy  from  the  cartilages  of  the  third,  fourth,  fifth  and  sixth  true  ribs,  and 
from  an  aponeurosis  common  to  it  and  the  external  oblique  muscle;  the  cla- 
vicular fibres  descend,  the  sternal  pass  horizontally,  and  the  costal  ascend 
obliquely ; all  pass  outwards  in  front  of  the  axilla  towards  the  humerus,  into 
which  they  are  inserted  by  a flat  tendon  into  the  anterior  edge  of  the  bicipital 
groove,  and  by  an  aponeurosis  into  the  fascia  of  the  arm;  a line  of  cellular 
membrane  separates  the  clavicular  from  the  sternal  portion ; in  some  cases 
these  appear  as  distinct  muscles.  Use,  the  clavicular  portion  can  raise  the 
arm  and  draw  it  forward,  the  sternal  can  press  it  to  the  side,  particularly  if 
assisted  by  the  latissimus  dorsi,  and  the  costal  portion  can  draw  it  down- 
wards and  forwards : the  whole  muscle  will  draw  the  arm  forwards  and 
inwards:  if  the  arm  have  been  rotated  outwards,  it  can  roll  it  inwards; 
if  the  arms  be  fixed,  and  this  pair  of  muscles  act,  they  will  draw  the  ribs 


OR  MANUAL  OF  ANATOMY. 


S3 


upwards  and  outwards,  and  thus  bj  enlarging  the  thorax  assist  in  inspiration. 
This  muscle  is  covered  by  the  skin,  platysma  and  mammary  gland,  and  its 
insertion  is  partly  concealed  by  the  deltoid ; it  covers  a portion  of  the  ster- 
num and  of  the  true  ribs,  also  the  subclavian  and  lesser  pectoral  muscles, 
the  thoracic  and  axillary  vessels  and  nerves.  Between  the  clavicular  portion 
of  this  muscle  and  the  anterior  edge  of  the  deltoid,  is  a space  filled  by  cel- 
lular tissue,  the  cephalic  vein  and  a small  artery.  The  tendinous  fibres  of 
the  sternal  portions  of  opposite  sides  decussate  each  other,  and  cover  the 
sternum  with  a sort  of  aponeurosis ; the  insertion  has  a twisted  appearance 
in  front  of  the  axilla,  the  sternal  and  costal  portions  being  folded  behind  the 
clavicular,  and  inserted  superior  and  posterior  to  it  into  the  anterior  edge  of 
the  bicipital  groove,  while  the  clavicular  is  united  to  the  deltoid,  and  is  in- 
serted into  the  humerus  along  with  that  muscle;  in  some  subjects  a bursa  may 
be  found  between  these  two  insertions  of  the  pectoral  muscle.  From  the 
lower  edge  of  the  costal  portion  a fleshy  slip  sometimes  descends  and  joins 
either  the  rectus  or  external  oblique  muscle  of  the  abdomen;  and  in  some  a 
strong  muscular  band  connects  it  to  the  inferior  margin  of  the  latissimus  dorsi. 
Make  a perpendicular  division  of  this  muscle,  reflect  the  edges,  one  towards 
the  sternum,  the  other  towards  the  shoulder;  and  the  lesser  pectoral  and  sub- 
clavian muscles  come  into  view. 

Pectoralis  Minor,  fiat  and  triangular,  arises  from  the  external  surface  and 
upper  edge  of  the  third,  fourth  and  fifth  ribs,  sometimes  from  the  second, 
external  to  their  cartilages;  the  fibres  ascend  obliquely  outwards  and  back- 
wards, and  converging,  end  in  a flat  tendon,  which  is  inserted  into  the  inner 
and  upper  surface  of  the  coracoid  process,  near  its  anterior  extremity,  being 
here  connected  with  the  coraco-brachialis  and  short-head  of  the  biceps ; a 
band  of  this  tendon  frequently  passes  over  this  process  through  the  triangular 
ligament,  and  is  connected  to  it,  or  to  the  tendon  of  the  supra-spinatus,  or  to 
the  capsular  ligament  of  the  shoulder.  Use,  to  draw  the  shoulder  forwards, 
downwards  and  inwards,  also  to  assist  the  great  pectoral,  in  elevating  the  ribs 
in  inspiration.  This  muscle  is  covered  by  the  great  pectoral,  a few  of  its 
inferior  fibres  are  covered  only  by  the  skin ; it  lies  anterior  to  the  serratus 
magnus,  axillary  vessels  and  nerves. 

Subclavius,  small  and  round,  arises  by  a flat  teudon,  from  the  cartilage  of 
the  first  rib,  external  to  the  rhomboid  ligament,  soon  becomes  fleshy,  and 
ascending  outwards  and  backwards,  is  inserted  into  the  external  half  of  the 
inferior  surface  of  the  clavicle,  extending  as  far  outwards  as  the  space  be- 
tween the  conoid  and  trapezoid  ligaments.  Use , to  draw  the  clavicle  and 
shoulder  forwards  and  downwards,  also  to  elevate  the  first  rib  in  inspiration, 
it  the  shoulder  and  clavicle  be  raised  and  fixed.  This  muscle  is  covered  by 
the  clavicle  and  great  pectoral;  it  lies  anterior  to  the  axillary  vessels  and 
nerves,  which  separate  it  from  the  first  rib  ; it  is  covered  by  a thin  but  strong 
aponeurosis,  which  is  attached  to  the  cartilage  of  the  rib,  and  to  the  clavicle 
and  subclavian  muscle,  from  which  it  passes  downwards  and  outwards  to  the 
coracoid , process,  arching  across  the  great  vessels,  and  is  then  connected  to 
that  process,  and  to  the  tendon  of  the  lesser  pectoral ; this  fascia  is  called  by 
some  the  coraco-clavicular  ligament;  it  is  sometimes  very  strong,  and  from 
the  manner  in  which  it  is  extended  over  the  vessels,  it  renders  it  difficult  to 
feel  the  pulsation  of  the  axillary  artery  below  the  clavicle. 

5 


34 


THE  DUBLIN  DISSECTOR. 


Serratus  Magnus,  thin  and  broad,  particularly  anteriorly,  placed  behind 
the  pectoral  muscles  and  the  axillary  vessels,  and  between  the  scapula  and 
the  ribs,  arises  by  eight  or  nine  fleshy  slips,  from  the  eight  or  nine  sup°rior 
ribs;  the  fibres  ascend  obliquely  backwards,  and  are  inserted  between  the 
subscapular,  the  rhomboid  and  levator  anguli  muscles  into  the  base  of  the 
scapula,  but  particularly  into  the  superior  and  inferior  angles.  Use,  to  draw 
the  scapula  forwards,  particularly  the  inferior  angle,  and  thus,  by  rotating  this 
bone  on  its  axis,  to  raise  the  acromion  process  and  the  shoulder  joint:  when 
the  upper  extremity  is  fixed,  this  muscle  can  raise  and  draw  outwards  the 
ribs,  so  as  to  assist  in  inspiration. — The  serratus  magnus  lies  on  the  ribs  and 
intercostal  muscles;  also  on  a portion  of  the  serratus  posticus ; external  to  it 
are  the  axillary  vessels,  the  scapula  and  subscapular  muscle;  the  trapezius, 
latissimus  dorsi  and  rhomboid  muscles  lie  behind  it,  and  the  pectoral  muscles 
are  anterior  to  it;  an  abundance  of  loose  cellular  membrane  connected  to  its 
surface  allows  it  to  glide  on  the  ribs,  and  also  facilitates  the  movements  of  the 
scapula  upon  it.  The  four  superior  digitations  lie  behind  those  of  the  lesser 
pectoral,  and  the  four  inferior,  which  are  only  covered  by  the  skin,  indigitate 
with  the  origins  of  the  external  oblique.  If  the  clavicle  be  separated  from 
the  sternum,  and  the  scapula  pulled  from  the  side,  this  muscle  will  then  be- 
come tense,  and  in  this  state  it  appears  to  consist  of  three  portions,  which 
differ  in  structure  and  in  form:  the  superior  is  a thick,  short  and  strong  fasci- 
culus, somewhat  square,  passing  from  the  two  first  ribs  beneath  the  axillary 
vessels  and  brachial  plexus,  to  the  superior  angle  of  the  scapula;  its  flat  sur- 
face is  directed  upwards,  and  lies  on  a plane  anterior  to  the  next  or  middle 
division,  which  is  very  thin,  consisting  of  but  few  fleshy  fibres,  connected 
together  by  an  aponeurosis.  This  portion  is  of  a triangular  form,  the  apex 
attached  to  the  3d  and  4th  ribs,  the  base  to  the  basis  of  the  scapula,  not  ex- 
actly to  the  bone,  but  to  a strong  tendinous  cord,  which  extends  along  this 
line  from  the  superior  to  the  inferior  angle.  The  third,  or  inferior  division  of 
the  serratus  is  the  strongest  and  most  extensive ; it  is  radiated  or  triangular; 
the  apex  thick  and  fleshy,  attached  to  the  inferior  angle  of  the  scapula ; the 
base  thin  and  expanded  on  the  ribs.  The  serratus  may  be  again  examined 
when  dissecting  the  muscles  on  the  back  of  the  trunk. 

Intercostales,  are  22  in  number  on  each  side,  11  external  and  11  inter- 
nal ; — the  external  commence  at  the  transverse  processes  of  the  dorsal  verte- 
brae, arise  from  the  inferior  edge  of  each  rib,  descend  in  fasciculi  obliquely 
forwards,  and  are  inserted  into  the  external  lip  of  the  superior  edge  of  the 
rib  beneath,  and  terminate  a little  behind  the  costal  extremity  of  the  carti- 
lages: an  aponeurosis,  the  fibres  of  which  run  in  the  same  direction,  supply 
their  place  as  far  as  the  sternum.  The  internal  intercostal  muscles  take  an 
opposite  direction,  and  decussate  the  former;  they  commence  at  the  sternum, 
and  are  discontinued  at  the  angles  of  the  ribs ; they  arise  from  the  inner  lip  of 
the  lower  edge  of  each  cartilage  and  rib,  the  fibres,  paler  and  shorter  than 
those  of  the  external,  descend  obliquely  backwards,  and  are  inserted  into  the 
inner  lip  of  the  superior  edge  of  the  cartilage  and  rib  beneath.  Use,  both 
laminae  co-operate  to  raise  the  ribs,  the  first  rib  being  fixed  by  the  scaleni. 
The  intercostal  muscles,  in  elevating  the  ribs,  also  evert  their  lower  edges, 
and  twist  them  at  their  vertebral  and  sternal  ends,  and  thus  assist  in  inspira- 
tion, by  enlarging  the  chest  transversely,  and  from  before  backwards.  The 


OR  MANUAL  OF  ANATOMY. 


35 


internal  layer  lies  on  the  pleura,  and  is  separated  from  the  external  by  the 
intercostal  vessels  and  nerves;  the  external  layer  is  connected  to  the  pleura 
only  in  the  space  between  the  angles  of  the  ribs  and  the  vertebrae.  At  the 
posterior  extremity  of  the  external  intercostal  muscles  there  are  the  following 
twelve  small  muscles,  which,  however,  may  be  seen  more  fully  when  the  mus- 
cles of  the  back  have  been  dissected. 

Levatores  Costarum,  arise  narrow  and  tendinous  from  the  extremity  of 
each  dorsal  transverse  process,  descend  obliquely  outwards,  and  are  inserted 
broad  into  the  upper  edge  of  the  rib  beneath,  between  its  tubercle  and  angle  ; 
their  name  denotes  their  use.  They  are  parallel  to,  and  frequently  appear  as 
a portion  of  the  external  intercostals ; the  first  levator  is  short,  and  arises 
from  the  last  cervical  vertebra;  the  inferior  increase  in  length  and  size. 

Behind  the  sternum  is  a small  muscle  which  cannot  be  seen  until  this  bone 
is  removed ; the  dissection  of  it,  therefore,  the  student  may  postpone,  until 
he  is  opening  the  cavity  of  the  thorax. 

Triangularis-Sterni,  arises  from  the  posterior  surface  and  edge  of  the 
lower  part  of  the  sternum,  and  from  the  xiphoid  cartilage  ; the  fibres  ascend 
obliquely  outwards,  the  inferior  pass  transversely — inserted  into  the  cartilages 
of  the  4th,  5th  and  6th  ribs.  Use,  to  depress  and  draw  backwards  the  carti- 
lages of  the  ribs,  so  as  to  assist  in  expiration.  These  muscles  lie  on  the 
pleurae,  pericardium,  and  diaphragm,  are  covered  by  the  sternum,  cartilages 
of  the  ribs,  and  mammary  vessels.  They  antagonize  the  external  intercostals, 
to  whose  fibres  they  are  parallel,  and  this  explains  the  cause  of  the  external 
intercostals  terminating  at  the  end  of  the  ribs,  and  not  continuing  as  far  for- 
wards as  the  sternum.  The  mechanism  of  respiration  shall  be  further 
considered'when  the  diaphram  has  been  examined  (see  dissection  of  it).  In 
connection  with  the  muscles  of  the  thorax,  the  student  should  study  the 
anatomy  of  the  axilla. 

§ £. — Dissection  of  the  Axilla. 

The  Axilla,  is  a conical  cavity,  the  apex  superiorly  at  the  coracoid  process 
aud  clavicle,  the  base  below,  formed  by  skin  and  a thick  fascia : it  is  bounded 
anteriorly  by  the  great  and  lesser  pectoral  muscles,  internally  by  the  serratus 
magnus  and  the  ribs,  externally  by  the  scapula  and  subscapular  muscle,  and 
posteriorly  by  the  serratus  and  latissimus  dorsi.  This  region  contains  several 
lymphatic  glands,  vessels  and  nerves,  and  a quantity  of  loose  cellular  and 
adipose  tissue,  which  is  continued  from  the  neck  beneath  the  clavicle,  and 
often  presents  a watery  reddish  appearance.  When  the  pectoral  muscles 
have  been  divided,  and  some  cellular  membrane  removed,  the  axillary  vein 
first  appears;  at  the  upper  part  of  the  axilla  this  vessel  is  internal  and  ante- 
rior to  the  artery  ; interiorly  it  is  directly  over  this  vessel,  and  more  closely 
connected  to  it  than  above;  this  vein  receives  the  cephalic  vein,  and  several 
branches  from  the  parietes  of  the  thorax,  and  from  the  shoulder,  i'he  axillary 
artery  may  be  next  seen,  taking  an  oblique  course  downwards  and  outwards 
through  this  space,  and  giving  off  thoracic  branches  from  its  internal  side  ; 
and  from  its  external,  the  subscapular  and  circumflex  arteries ; behind  the 
artery,  at  the  upper  part  of  the  axilla,  the  brachial  plexus  of  nerves  is  seen; 
as  this  descends  it  becomes  more  and  more  closely  connected  to  it,  and  at  the 


56 


THE  DUBLIN  DISSECTOR, 


lower  part  of  this  cavity  the  branches  of  the  plexus  have  almost  surrounded 
the  artery.  The  plexus  may  be  seen  dividing  into  several  branches;  supe- 
riorly, it  gives  off  the  thoracic,  supre  and  subcapsular ; and  lower  down  it 
divides  into  the  external  and  internal  cutaneous,  the  median,  ulnar,  radial  or 
spiral,  and  articular  or  circumflex.  The  general  distribution  of  these  branches 
will  be  noticed  in  the  dissection  of  the  upper  extremity,  and  for  their  parti- 
cular description  see  Anatomy  of  the  Nervous  System.  At  the  lower  part 
of  the  axilla  the  artery  may  be  observed  in  general  to  lie  between  the  two 
roots  of  the  median  nerve,  with  the  external  cutaneous  to  its  outer  or  humeral 
side,  and  with  the  ulnar  and  internal  cutaneous  to  its  inner  or  thoracic  side, 
while  posterior  to  it  are  the  musculo-spiral  and  articular  nerves.  The  lym- 
phatic glands  are  connected  to  the  axillary  vessels  by  the  small  branches 
which  supply  them  : several  lie  posterior  to  the  edge  of  the  pectoral  muscle ; 
from  these  a chain  continues  up  to  the  coracoid  process,  and  are  continued 
beneath  the  clavicle  and  the  glands  in  the  neck;  several  also  lie  on  the  sub- 
scapular muscle,  and  some  are  scattered  indifferently  through  this  space. 

§ 3. — Dissection  of  the  Cavity  of  the  Thorax. 

The  thorax  is  situated  at  the  upper  and  anterior  part  of  the  trunk  ; it  con- 
tains the  lungs, the  organs  of  respiration,  the  heart,  the  chief  agent  in  the  cir- 
culation of  the  blood,  also  several  nerves  and  vessels  passing  to  and  from  the 
heart,  and  through  the  cavity ; this  region  is  bounded  anteriorly  by  the  sternum 
and  costal  cartilages,  laterally  by  the  ribs  and  intercostal  muscles,  posteriorly 
by  the  vertebrae  and  angles  of  the  ribs,  interiorly  by  the  diaphragm,  superiorly 
by  the  several  muscles  connected  to  the  clavicle,  first  rib  and  sternum,  and 
by  the  different  parts  passing  into  or  out  of  the  cavity.  The  thorax,  viewed 
externally,  presents  a very  different  form  before  and  after  the  upper  extremi- 
ties are  detached  from  it;  in  the  former  state  it  appears  of  great  transverse 
width  above,  and  narrow  below ; whereas  in  the  latter  condition,  it  is  seen  to 
be  very  contracted  above  and  expanded  below.  The  thorax  may  be  compared 
to  a section  of  a cone,  the  posterior  fourth  being  removed,  three  anterior  parts 
retained  and  united  to  each  other.  The  axis  of  the  cavity  is  oblique  from 
above  downwards  and  forwards;  the  base  of  the  thorax  is  also  oblique  from 
before,  backwards  and  downwards,  and  the  apex  on  the  contrary  is  oblique 
from  behind,  forwards  and  downwards;  hence  the  perpendicular  diameter  of 
the  thorax  is  much  greater  posteriorly  than  it  is  behind  the  sternum.  The 
apex  of  the  thorax  is  somewhat  truncated,  and  presents  an  oval  opening  longer 
transversely  than  from  before  backwards  ; this,  the  superior  orifice  of  the 
thorax , is  bounded  anteriorily  by  the  upper  edge  of  the  sternum  and  nter- 
davicular  ligament,  posteriorly  by  the  last  cervical  and  first  dorsal  vertebra, 
and  laterally  by  the  first  rib : the  several  important  parts  which  pass  th  ough 
this  opening  shall  be  noticed  afterwards.  The  inferior  circumference  < f the 
thorax  is  five  or  six  times  more  extensive  than  the  superior;  it  is  bourn  d by 
the  xiphoid,  the  last  true  and  all  the  false  costal  cartilages,  and  by  th  last 
dorsal  and  first  lumbar  vertebrae  ; its  longer  diameter  is  also  trails  erse. 
Open  the  cavity  by  dividing  the  cartilages  of  the  ribs  on  each  side  of  th-  ster- 
num, and  raising  the  latter  from  below  upwards  ; if  we  look  under  the  st<  num 
as  we  thus  slowly  raise  it,  we  perceive  that  space  called  anterior  media'  man 


OR  MANUAL  OF  ANATOMY. 


37 


to  be  gradually  developed,  from  the  right  and  left  pleurae  separating  from  each 
other  as  we  tear  the  loose  cellular  membrane  which  naturally  connects  the 
pleurae  and  pericardium  to  the  posterior  surface  of  the  bone  : when  the  sternum 
is  removed  this  region  is  fully  exposed  ; it  is  described  as  being  of  a triangular 
form,  the  base,  the  sternum  ; the  sides,  the  pleurae,  converging  behind  so  as 
nearly  to  touch  each  other  ; the  apex,  the  small  portion  of  pericardium  left 
uncovered  by  the  pleurae  ; naturally,  however,  all  the  parts  within  the  thorax 
are  so  closely  applied  to  the  parietes,  that  no  space  or  cavity  of  a defined 
form,  like  that  assigned  to  the  anterior  mediastinum,  can  truly  be  said  to  ex- 
ist. The  dissector,  however,  may  cause  this  space  to  appear  more  distinct  by 
the  following  precaution  : before  you  divide  the  cartilages,  push  your  fingers 
from  the  abdomen  behind  the  sternum,  and  break  down  the  cellular  connections 
between  it  and  the  pleurae,  then  cut  the  cartilages  very  near  the  sternum,  and 
raise  the  latter ; without  this  precaution  before  dividing  the  cartilages,  the 
pleura,  particularly  the  right,  will  be  in  almost  every  instance  laid  open,  and 
so  the  appearance  of  the  anterior  mediastinum  injured.  This  region  in  gen- 
eral inclines  a little  to  the  left  side  below,  in  consequence  of  the  left  pleura 
being  more  attached  to  the  pericardium,  which  lies  rather  to  the  left  of  the 
middle  line,  whereas  the  right  pleura  is  connected  to  the  sternum  in  a vertical 
line:  the  anterior  mediastinum  is  wider  superiorly  and  inferiorly  than  in  the 
centre,  hence  some  compare  it  to  the  letter  X,  and  describe  it  as  consisting  of 
two  triangular  spaces,  their  apices  joined  in  the  centre,  the  base  of  one  towards 
the  neck,  and  that  of  the  other  towards  the  diaphragm:  the  superior  portion 
contains  the  origins  of  the  sternohyoid  and  thyroid  muscles  and  the  remains 
of  the  thymus  gland  ; inferiorly  there  is  much  loose  cellular  membrane,  which 
leads  from  the  neck  to  the  abdominal  muscles,  also  lymphatic  glands,  and 
close  to  the  sternum  are  the  mammary  vessels,  and  the  triangulares  sterni 
muscles.  Next  examine  the  organs  on  each  side  of  the  thorax ; these  are  the 
lungs  and  their  investing  membrane  the  pleura  ; in  almost  all  respects  these 
organs  are  similar  on  the  right  and  left  side,  and  therefore  either  may  be  se- 
lected for  examination  ; for  this  purpose  lay  open  one  side,  suppose  the  right, 
of  the  thorax,  by  sawing  through  the  ribs  about  their  centre,  and  removing 
their  anterior  portion  ; the  first  rib  may  be  left  uninjured  ; thus  the  cavity  of 
the  right  pleura  will  be  opened,  its  glistening  surface  seen,  with  the  lung  lying 
collapsed.  Th e pleurae  are  serous  membranes,  their  internal  surface  is  smooth, 
polished,  and  free  ; their  external  surface  is  connected  by  fine  cellular  mem- 
brane to  the  parietes  of  the  thorax  and  to  the  tissue  of  the  lungs,  over  which 
they  are  reflected.  That  portion  of  each  which  invests  the  lungs  is  called 
pleura  pulmonalis,  and  that  which  is  connected  to  the  parietes  pleura  parietalis 
or  costalis  ; the  latter  portion  of  the  membrane  is  much  more  dense  and  strong 
than  the  former;  each  pleura  is  a shut  sac,  and  contains  only  the  serous  vapor 
it  exhales;  for  altliough  the  lung  appears  within  the  cavity,  it  is  yet  really 
external  to  it  or  behind  it;  internally  each  pleura  presents  one  continuous 
surface,  which  can  be  traced  throughout  its  whole  extent;  thus  we  can  per- 
ceive that  the  right  pleura  passes  from  the  back  of  the  sternum  to  form  the  side 
of  the  anterior  mediastinum,  and  arriving  at  the  fore  part  of  the  pericardium 
is  continued  along  the  side  of  that  bag  as  far  back  as  the  root  of  the  lung, 
whence  it  is  reflected  over  the  anterior  surface  of  this  organ,  sinking  into  its 
fissures,  and  connecting  all  its  lobules  to  each  other;  having  thus  invested  the 


38 


THE  DUBLIN  DISSECTOR, 


whole  lung,  it  arrives  at  the  posterior  surface  of  its  root,  from  which  it  is  re- 
fleeted  to  the  back  part  of  the  pericardium,  where  it  approaches  the  opposite 
pleura,  to  which  it  is  connected  by  cellular  membrane  ; thence  it  passes  to  the 
sides  of  the  vertebrae,  thus  forming  the  side  of  the  posterior  mediastinum  (to 
be  examined  presently) ; the  pleura  then  expands  along  the  side  of  the  spine, 
ascending  as  high  as  the  transverse  process  of  the  6th  or  7th  cervical  vertebra, 
and  descending  to  the  diaphragm,  the  convex  surface  of  which  it  covers;  on 
this  muscle  also  it  is  reflected  from  the  lower  edge  of  the  root  of  the  lung  by 
a fold  called  ligamentum  latum  pulmonis,  loose  and  triangular,  the  base  to- 
wards the  diaphragm,  one  side  connected  to  the  lung,  and  the  opposite  to  the 
mediastinum  ; from  the  vertebrae,  the  pleura  continues  to  pass  outwards,  lining; 
the  ribs  and  intercostal  muscles,  as  far  forwards  as  the  side  of  the  sternum, 
where  the  sac  was  opened,  and  the  description  commenced.  The  pleurae  are 
of  a conical  form,  the  apex  of  each  is  in  the  neck,  covered  by  the  anterior 
scalenus  and  subclavian  artery,  the  base  adheres  to  the  diaphragm;  the  right 
pleura  is  shorter  but  broader  than  the  left,  which  is  long  and  narrow;  the  liver 
on  the  right  side  and  the  heart  on  the  left,  cause  these  differences  to  exist; 
the  apex  of  the  right  is  often  higher  in  the  neck  than  that  of  the  left.  The  two 
pleurae  have  been  resembled  to  two  bladders  placed  nearly  parallel  to  each 
other,  not  having  any  communication,  but  touching  each  other  along  the  mesial 
line;  this  juxta-position  of  the  two  pleurae  between  the  sternum  and  vertebrae 
forms  a sort  of  partition  between  the  right  and  left  sides  of  the  thorax  ; this 
partition  is  called  mediastinum ; it  consists  of  course  of  two  laminm,  right  and 
left,  connected  anteriorly  to  the  sternum,  posteriorly  to  the  spine;  these 
laminae  are  separated  from  each  other  in  three  situations,  in  order  to  enclose 
certain  organs,  so  that  the  mediastinum  is  divided  into — 1st,  the  anterior  part, 
or  anterior  mediastinum,  which  has  been  already  examined  ; 2d,  into  a mid- 
dle part,  or  middle  mediastinum,  containing  the  heart  and  pericardium  ; and 
3d,  into  a posterior  mediastinum)  which  lies  in  front  of  the  vertebra,  and  which 
the  student  may  next  examine. 

The  posterior  mediastinum  extends  in  a vertical  direction  from  the  3d  to 
the  10th  dorsal  vertebra,  behind  the  pericardium  and  roots  of  the  lungs,  and 
in  front  of  the  spine ; to  obtain  a view  of  the  parts  contained  in  it,  draw  the 
right  lung  forward,  and  to  the  left  side,  and  make  a perpendicular  division  of 
the  right  pleura,  between  the  root  of  the  lung  and  the  spine.  This  region  is 
described  as  being  of  a tiiangular  form,  the  base  posteriorly,  the  pleura  form- 
ing its  sides,  and  the  pericardium  its  apex;  like  the  anterior  mediastinum, 
however, ’it  has  naturally  no  exact  figure,  the  pleurae  being  folded  round  the 
organs  which  lie  between  them.  In  the  posterior  mediastinum  we  find  the 
(esophagus  and  8th  pair  of  nerves,  the  thoracic  duct,  vena  azygos,  descend- 
ing aorta,  splanchnic  nerves,  several  lymphatic  glands,  and  a considerable 
quantity  of  fine,  loose  cellular  membrane  ; the  division  of  the  trachea  also  is 
enclosed  in  this  space,  just  at  its  commencement.  The  oesophagus  is  anterior 
to  the  other  parts  in  the  posterior  mediastinum ; this  tube  having  passed  behind 
the  left  division  of  the  trachea,  enters  this  space,  and  descends  obliquely  for- 
wards behind  the  pericardium  and  before  the  aorta  ; above,  it  lies  to  the  right 
side  of  this  vessel,  but  below  it  is  to  the  left ; in  the  lower  part  of  its  course  it 
is  surrounded  by  branches  of  the  8th  pair  of  nerves,  and  enlarging  a little, 
it  perforates  the  fleshy  part  of  the  diaphragm,  opposite  the  9th  or  10th  dorsal 


OR  MANUAL  OF  ANATOMY. 


39 


vertebra,  and  joins  the  stomach.  The  8th  pair  of  nerves  having  passed  behind  the 
roots  of  the  lungs,  attach  themselves  to  the  oesophagus,  form  by  their  branches 
a plexus  around  it,  (the  oesophageal  plexus) ; the  left  nerve  then  descends 
on  the  fore,  and  the  right  on  the  back  part  of  this  tube  to  the  stomach.  The 
thoracic,  aorta  enters  this  region  about  the  4th  or  5th  dorsal  vertebra,  and 
descends  along  the  left  side  of  the  spine;  about  the  11th  or  12th  dorsal 
vertebra  it  passes  between  the  crura  of  the  diaphragm  into  the  abdomen  ; in 
this  course  the  aorta  furnishes  the  following  branches ; two  or  three  bronchial 
arteries,  which  go  to  the  lungs,  as  many  oesophageal  branches,  and  nine  or  ten 
pair  of  intercostal  arteries,  whose  name  implies  their  destination. 

The  vena  azygos  commences  in  the  abdomen  by  a small  branch  from  one 
of  the  superior  lumbar  veins,  enters  the  thorax  behind  the  right  side  of  the 
posterior  mediastinum,  covered  by  the  right  pleura;  and  opposite  the  3d  or 
4th  dorsal  vertebra  it  arches  forward  over  the  root  of  the  right  lung,  and  opens 
into  the  superior  vena  cava,  as  that  vessel  is  entering  the  pericardium.  The 
vena  azygos  in  this  course  receives  the  bronchial,  oesophageal,  and  intercostal 
veins  ; those  of  the  leftside  often  unite  into  one  branch,  which  passing  behind 
the  aorta,  joins,  opposite  the  6th  or  7th  vertebra,  the  principal  trunk  on  the 
right  side.  The  thoracic  cluct  also  commences  in  the  abdomen,  on  the  2d  or 
3d  vertebra,  behind  the  aorta,  in  a sinus,  called  receptaculum  chyli : contract- 
ing in  size  it  enters  the  posterior  mediastinum  along  with  and  to  the  right  side 
of  the  aorta;  it  ascends  between  this  vessel  and  the  vena  azygos,  imbedded 
in  fat,  and  opposite  to  the  5th  or  6th  dorsal  vertebra  it  attaches  itself  to  the 
back  of  the  oesophagus,  runs  obliquely  along  it,  behind  the  arch  of  the  aorta, 
to  the  left  side,  and  ascends  in  the  neck  behind  the  left  carotid  artery  and 
jugular  vein,  as  high  as  the  6th  cervical  vertebra  ; it  then  bends  downwards 
and  outwards,  and  enters  the  left  subclavian  just  before  it  joins  the  jugular 
vein.  The  coats  of  the  thoracic  duct  are  so  fine  and  thin,  that  it  is  often 
difficult  to  see  or  trace  this  vessel.  For  a more  particular  description  of  it, 
see  the  Anatomy  of  the  Absorbent  System.  The  splanchnic  nerves  arise  by 
four  or  five  filaments  from  the  dorsal  ganglions  of  the  sympathetic  nerve  ; the 
first  is  from  the  5th  or  6th  ganglion,  the  rest  arises  in  succession  below  it;  all 
unite  and  form  the  splanchnic  nerves,  which  descend  obliquely  forward  on 
each  side  of  the  aorta,  along  with  which  they  enter  the  abdomen,  where  each 
terminates  in  a large  ganglion,  termed  semilunar;  these  two  ganglions  are 
joined  together  by  numerous  branches,  which  constitute  the  cce/iac,  or  solar 
plexus , from  which  the  greater  number  of  abdominal  viscera  are  supplied  with 
nerves.  In  the  dissection  of  the  posterior  mediastinum,  the  sympathetic 
nerve  is  also  seen  on  each  side  ; it  does  not  lie  in  this  space,  but  descends  ex- 
ternal to  it,  between  the  pleurae  and  the  heads  of  the  ribs;  opposite  each  inter- 
costal space  it  forms  a ganglion,  from  which  some  branches  pass  to  join  the 
dorsal  spinal  nerves,  others  to  form  the  great  splanchnic  ; and  at  the  lower 
part  ol  the  thorax  two  or  three  filaments  often  unite  to  form  a small  nerve, 
called  lesser  splanchnic,  which  enters  the  abdomen  behind  or  through  the  crura 
ot  the  diaphragm,  and  joins  the  renal  plexus  of  nerves.  The  sympathetic  on 
each  side  enters  the  thorax  close  to  the  neck  of  the  first  rib,  where  it  forms  a 
large  ganglion  ; it  passes  from  the  cavity  by  a very  small  filament,  between 
the  crus  of  the  diaphragm,  and  the  psoas  magnus,  into  the  abdomen,  where  it 
again  enlarges  considerably.  See  the  Anatomy  of  the  Nervous  System. — The 


40 


THE  DUBLIN  DISSECTOR, 


di-vision  of  the  trachea,  the  last  part  of  any  importance  connected  with  the 
posterior  mediastinum,  does  not,  strictly  speaking,  lie  in  this  space,  but  like 
the  heart  and  great  vessels,  it  is  in  the  middle  mediastinum,  or  between  the 
anterior  and  posterior ; this  tube  can  be  more  conveniently  examined  after- 
wards, when  we  are  dissecting  the  parts  which  pass  through  the  upper  opening 
of  the  thorax.  Next  examine  the  lungs. 

The  lungs  are  situated  at  either  side  of  the  spine,  and  when  distended  with 
air,  as  they  always  are  during  life,  they  so  exactly  fill  each  side  of  the  thorax 
that  the  pleura  pulmonalis  and  costalis  are  always  in  such  perfect  apposition, 
that  there  never  can  be  any  intermediate  cavity;  they  are  of  a conical  figure, 
the  apex,  above,  rises  into  the  neck  a little  above  the  level  of  the  first  rib,  and 
in  general  higher  on  the  right  than  on  the  left  side ; the  base,  below,  concave, 
rests  on  the  diaphragm  : the  external  surface  convex,  and  divided  into  two  oi 
three  parts  by  a deep  fissure  ; the  internal  slightly  concave,  and  attached  neai 
its  centre  by  the  root  of  the  heart  and  great  vessels;  the  posterior  edge  of 
each  lung  is  thick,  round,  and  vertical ; the  anterior  is  thin,  irregular,  oblique, 
anil  shorter  than  the  posterior;  that  of  the  left  side  is  in  general  notched  op- 
posite the  apex  of  the  heart.  The  right  lung  is  broader  but  shorter  than  the 
left,  the  former  consists  most  commonly  of  three  lobes,  the  latter  has  only  two 
The  great  fissure  of  each  lung  descends  obliquely  forwards  ; it  commences  be- 
hind the  apex,  and  ends  in  front  of  the  bases;  it  divides  the  substance  of  the 
lung,  to  a great  depth,  in  two  lobes  ; one  is  anterior  and  superior,  and  the  other 
posterior  and  inferior  ; the  latter  is  somewhat  larger ; on  the  right  side  a small 
fissure  leads  from  about  the  middle  of  the  great  one,  forwards  to  the  edge  of 
the  lung,  and  cuts  off  the  middle  lobe  from  the  superior  ; this  fissure  does  not 
penetrate  to  the  same  depth  a9  the  great  one  does  ; it  is  sometimes  absent,  and 
in  seme  subjects  it  exists  on  the  left  as  well  as  on  the  right  side.  The  root 
of  each  lung  is  situated  a little  above  the  centre  of  the  internal  surface,  and 
about  two-thirds  from  the  anterior  edge;  the  phrenic  nerve  and  a few  filaments 
of  the  pneumogastric  lie  anterior  to  it,  and  the  pulmonary  plexus  is  posterior 
to  it;  the  fold  called  ligamentum-latum  is  below  it;  it  consists  of  several  ves- 
sels and  nerves  connected  together  by  cellular  tissue,  and  all  enclosed  between 
the  laminae  of  pleura ; dissect  off  this  membrane  from  the  fore  part  of  the  root, 
and  we  shall  observe  the  two  pulmonary  veins  inferior,  but  anterior  to  the 
pulmonary  artery,  which  is  immediately  above  and  behind  them  ; posterior 
and  superior  to  the  artery  is  the  bronchial  tube;  a quantity  of  cellular  tissue 
connects  these  vessels,  and  contains  the  bronchial  arteries  and  veins,  also 
several  nerves,  which  are  derived  from  the  pulmonary  plexus.  In  the  root  of 
the  left  lung  the  bronchial  tube  is  rather  inferior  to  the  artery,  but  still  pos- 
terior to  it,  as  on  the  right  side.  The  lungs  have  a peculiar  soft,  emphysema- 
tous feel,  and  are  so  light  as  to  float  in  water ; their  color  is  gray,  interspersed 
with  spots  of  dark  blue  or  blackish  tint ; the  younger  the  subject  the  redder 
the  lungs  will  be  found;  in  the  adult  they  are  generally  gray,  and  slightly 
streaked  with  dark  lines ; in  the  old  they  are  usually  mottled  with  blue  or 
black  spots,  which  exist,  not  merely  on  the  surface,  but  through  their  substance. 
The  lungs  are  composed  of  the  ramifications  of  the  pulmonary  arteries  and 
veins,  of  the  bronchial  arteries  and  veins,  of  the  pulmonary  nerves,  of  lymph- 
atic vessels  and  glands,  and  of  the  ramifications  of  the  bronchial  tubes,  which 
end  in  numerous  air  cells  ; these  are  collected  at  first  in  clusters,  and  joined 


OR  MANUAL  OF  ANATOMY. 


41 


by  cellular  membrane  into  lobules : these  last  are  again  united  into  larger 
masses  by  the  pleura,  so  as  to  form  lobes;  the  air-cells  are  the  terminations  of 
the  bronchial  vessels;  they  are  globular,  are  lined  by  mucous  membrane  and 
covered  by  a fibrous,  or,  as  some  suppose,  a muscular  lamina;  each  bronchus 
divides  into  two  branches,  these  again  subdivide  into  two,  and  so  on  in  binary 
order  ; these  canals  increase  in  number,  and  diminish  in  size;  their  final  capil- 
lary branches  end  in  small  sacs  or  air  cells ; these  constitute  the  principal  bulk 
of  the  lung:  the  larger  bronchial  tubes  are  composed  of  the  same  materials  as 
the  trachea,  but  in  the  smaller  branches  there  is  no  cartilaginous  structure. 
On  their  delicate  parietes  the  fine  capillaries  of  the  pulmonary  arteries  and 
veins  are  spread,  and  here  during  life  is  effected  that  important  change  in  the 
blood,  from  venous  to  arterial,  which  appears  to  be  the  great  design  of  the  func- 
tion of  respiration.  The  soft  and  yielding  tissue  of  the  lungs  admits  of  the 
free  entrance  and  rapid  circulation  of  the  air  through  their  cells,  all  which  be- 
come distended  in  the  moment  of  inspiration ; in  this  act  the  lungs  are  wholly 
passive,  the  air  distending  them  in  the  exact  proportion  with  which  the  parietes 
of  the  chest  are  expanded ; in  expiration,  the  contraction  of  the  thorax  ex- 
pels a great  portion  of  the  air  from  the  cells,  and  thus  the  lungs  become  dimin- 
ished in  capacity ; in  effecting  this  change  the  elasticity,  aided  in  all  probability 
by  the  irritable  or  muscular  energy  of  these  organs  may  assist  the  muscular 
and  elastic  power  of  the  parietes  of  the  chest.  In  expiration  the  air-  cells  ar6 
not  wholly  emptied  ; no  power  can  completely  discharge  the  air  from  lungs 
that  have  once  breathed.  See  Anatomy  of  the  Diaphragm. — We  shall  next 
direct  our  attention  to  the  pericardium  and  the  heart. 

The  pericardium  is  a strong  fibro-serous  membrane,  in  the  form  of  a conical 
bag,  whose  base  is  below  and  apex  above  ; it  is  larger  than  the  heart,  which 
it  encloses,  together  with  a portion  of  the  great  vessels  connected  to  it,  and 
over  whose  surface  its  internal  or  serous  layer  is  reflected  : the  external  fibrous 
lamina  is  connected,  interiorly,  to  the  central  division  of  the  cordiform  tendon 
of  the  diaphragm,  and  to  some  of  its  fleshy  portion  between  the  central  and 
the  left  divisions  of  that  tendon  ; anteriorly,  to  the  pleurse,  and  to  the  parts 
contained  in  the  anterior  mediastinum ; posteriorly,  to  the  oesophagus  and  to 
the  other  parts  in  the  posterior  mediastinum  ; superiorly,  it  is  continued  along 
the  outer  coat  of  the  great  vessels,  while  the  serous  layer  is  reflected  on  these 
towards  the  heart.  On  each  side  it  is  in  a similar  manner  connected  to  the 
pulmonary  vessels  ; the  pleura  and  the  phrenic  nerve  also  are  attached  to  it 
in  this  situation.  The  connection  between  it  and  the.  tendon  of  the  diaphgram 
particularly  towards  its  fore  part  is  very  intimate;  in  the  adult  they  are  al- 
most inseparable,  not  so  however  in  the  foetus.  Open  this  bag,  and  we  shall  see 
that  it  is  lined  throughout  by  a smooth  serous  membrane,  which  if  we  trace 
to  the  superior  part  of  the  sac  we  shall  perceive  to  be  reflected  on  the  vena 
cava  on  the  right  side,  on  the  aorta  in  the  middle,  and  on  the  pulmonary  artery 
on  the  left  side;  on  these  three  vesselsitdescendstowards  the  heart : there  isa 
longer  portion  of  the  aorta  covered  by  the  serous  membrane  than  of  the  vena  ca- 
va or  pulmonary  artery,  which  two  are  nearly  equal  in  this  respect.  The  serous 
layer  is  reflected  on  the  superior  cava,  opposite  the  entrance  of  the  vena 
azygos  ; as  it  descends  along  that  vessel  it  nearly  surrounds  it,  except  a small 
portion  of  it  posteriorly ; from  the  vena  cava  it  continues  to  the  right  auricle, 
which  it  covers  anteriorly  and  on  the  right  side  ; from  this  it  passes  on  the 
6 


42 


THE  DUBLIN  DISSECTOR, 


right  pulmonary  veins,  covers  these  partially,  and  is  thence  reflected  to 
the  fibrous  layer;  from  the  lower  part  of  the  right  auricle  it  is  continued 
partly  round  the  inferior  cava,  and  from  it  also  it  is  reflected  to  the  fibrous 
layer.  On  the  aorta  the  serous  layer  decends  as  first  on  the  forepart,  after- 
wards on  its  sides  and  back  part,  so  as  to  encircle  it ; near  the  heart  it  passes 
from  it  over  the  pulmonary  artery,  so  as  to  connect  these  vessels  to  each  other, 
leaving  of  course  uncovered  so  much  of  each  as  are  in  apposition  ; along  these 
vessels  the  serous  membrane  decends  to  the  ventricles,  and  having  covered  all 
the  anterior  surface  of  the  heart,  it  turns  round  its  apex,  covers  the  posterior 
surface,  and  ascending  on  it  as  high  as  the  upper  edge  of  the  left  auricle,  it 
is  thence  reflected  on  the  fibrous  layer  in  front  of  the  posterior  mediastinum; 
from  the  left  auricle  also  it  extends  to  the  left  pulmonary  veins,  from  which 
it  is  continued  to  the  fibrous  layer,  and  on  this  we  can  trace  it  in  an  uninter- 
rupted course  to  that  point,  at  which  we  commenced  its  description. 

The  pericardium,  by  its  fibrous  lamina,  is  of  use  in  fixing  the  heart  in  its 
situations,  and  strengthening  its  parietes,  so  as  to  resist  over  distention ; this 
tunic  also,  by  its  elasticity,  may  assist  in  the  subsequent  contraction  of  its 
cavities,  while  the  serous  layer  being  always  lubricated  by  a fine  fluid,  facili- 
tates the  motion  of  the  heart.  When  the  pericardium  is  fullv  opened,  the 
right  auricle,  the  two  cavte  the  appendix  of  the  left  auricle,  the  right  or  ante- 
rior ventricle,  that  small  portion  of  the  left  which  forms  the  apex  of  the  heart, 
the  aorta  and  pulmonary  artery,  also  branches  of  the  coronary  vessels,  rami- 
fying on  the  anterior  surface  of  the  heart,  all  come  into  view. 

The  heart  is  placed  obliquely  between  the  lungs,  the  base  of  it  is  superior, 
posterior,  to  the  right  side,  and  near  to  the  spine,  while  the  apex  points  towards 
the  costal  end  of  the  cartilage  of  the  6th  rib  on  the  left  side,  and  during  life 
can  be  felt  pulsating  a little  above  and  below  this  rib;  the  heart  is  retained  in 
situ  by  the  pericardium,  and  by  the  great  vessels  ; it  is  subject,  however,  to  a 
slight  change  of  position,  according  as  that  of  the  body  is  altered,  as  well  as 
from  the  different  states  of  inspiration  and  expiration.  The  heart  consists  of 
four  cavities,  two  ventricles,  and  two  aurcles;  these  the  student  may  examine 
in  that  order  or  course  which  the  blood  pursues  in  passing  through  this  organ. 
Suppose  the  two  venae  cavae  pour  their  blood  into  the  right  auricle  so  as  to 
distend  it,  the  parietes  of  this  cavity  then  contract,  and  empty  its  contents  into 
the  right  ventricle  ; this  next  propels  the  blood  into  the  pulmonary  artery,  the 
branches  of  which  convey  it  through  the  lungs;  from  these  organs  it  is  returned 
by  the  four  pulmonary  veins,  two  on  each  side,  into  the  left  auricle  ; from  this 
cavity  it  is  forced  into  the  left  ventricle,  which  then  propels  it  into  the  aorta, 
through  whose  branches  it  is  conveyed  to  all  parts  of  the  body,  whence  it  is 
again  returned  to  the  heart  by  the  veins.  The  superior  vena  cava  is  seen  de- 
scending obliquely  forwards  and  inwards  within  the  pericardium,  and  joining 
the  upper  and  back  part  of  the  right  auricle.  Of  the  inferior  cava  but  a shorr 
portion  is  seen  within  the  pericardium  ; this  vessel  lies  on  a plane  posierior  to 
the  superior  cava,  and  passing  obliquely  upwards,  backwards,  and  inwards, 
joins  the  lower  and  back  part  of  the  right  auricle.  Between  these  two  veins 
the  right  auricle  is  situated;  it  is  somewhat  square,  its  posterior  part,  between 
the  two  cavae,  is  called  the  sinus ; the  anterior  loose  portion,  the  auricular  appen- 
dix or  process  ; the  right  auricle  is  connected  inferiorily  to  the  right  ventricle, 
and  partly  rests  on  the  diaphram  ; on  the  right  side  it  is  free,  and  on  the  left  it 


OR  MANUAL  OF  ANATOMY. 


43 


is  connected  to  the  left  auricle  ; lay  open  this  cavity  by  a perpendicular  incision 
from  the  superior  down  to  within  half  an  inch  of  the  inferior  cava,  from  the 
centre  of  this  make  a transverse  cut  towards  the  anterior  part  of  the  auricle, 
wash  out  the  blood,  and  we  may  then  observe  at  the  back  part  of  the  sinus 
the  openings  of  the  two  cavae,  and  between  these  a slight  projection  tuber- 
culum  Loweri;  and  in  the  auricular  appendix  the  muscular  fibres  called 
musculi  pectinati.  We  can  also  now  perceive  that  the  left  or  internal  side  of 
the  auricle  is  formed  by  a thin  sheet  of  membranous  and  muscular  substance; 
this  is  the  septum  auricularum  ; on  the  inferior  part  of  this  we  may  observe  a 
depression,  the  fossa  ovalis,  immediately  above  the  inferior  cava,  and  sur- 
rounded in  part  by  a thick  lip,  named  its  annulus  ; at  the  upper  and  deeper  part 
of  this  fossa  we  frequently  find  a small  oblique  passage  leading  into  the  left 
auricle,  its  obliquity,  however,  prevents  any  communication  taking  place 
during  life ; in  the  foetus  before  birth  this  was  a free  opening,  the  foramen  ovale, 
between  the  two  auricles  ; anterior  to  the  opening  of  the  inferior  cava  we  ob- 
serve the  semilunar  fold  of  the  lining  membrane,  the  Eustachian  valve ; this 
valve  is  connected  by  its  convex  edge  to  the  angle  between  the  vein  and  auri- 
cle; its  concave  edge  is  loose,  and  looks  backwards  and  to  the  right  side;  its 
superior  cornu  is  connected  to  the  anterior  or  the  left  limbus  of  the  fossa  ovalis, 
and  the  inferior  to  the  fore  part  of  the  vena  cava;  this  cornu  is  sometimes  con- 
tinued round  that  vessel  to  the  posterior  limbus  of  the  fossa  ovalis  ; in  the  adult 
and  old  this  valve  is  often  reticulated  and  imperfect ; in  the  foetus  it  is  generally 
more  perfect  and  large,  hence  it  is  considered  by  many  as  being  of  use  at  that 
period  in  directing  the  blood  from  the  inferior  cava  at  once  into  the  left  auricle 
through  the  foramen  ovale,  and  preventing  its  mixing  with  that  from  the  supe- 
rior cava.  To  the  left  side  of  the  Eustachian  valve,  between  it  and  the  ven- 
tricle, is  the  orifice  of  the  coronary  vein,  which  is  also  partly  covered  by  a 
semilunar  fold  of  membrane,  the  valve  which  secures  this  opening  against  the 
re-entrance  of  the  blood  during  the  contraction  of  the  auricle ; this  valve  also  is 
often  imperfect;  on  different  parts  of  the  auricle  small  orifices  may  be  often 
seen  (foramina  Thebesii) ; these  are  probably  the  extremities  of  small  veins. 

In  the  anterior  part  of  the  auricle  we  see  the  small  circular  opening  of  the 
appendix,  inferior  to  which,  and  opposite  the  tuberculum  Loweri,  is  the  large 
orifice  leading  into  the  right  ventricle  ; this,  the  right  auriculo-ventricular 
opening,  is  circular,  and  surrounded  by  a dense  white  line,  which  has  been 
erroneously  described  as  the  right  tendon  of  the  heart.  We  may  next  ex- 
amine the  right  ventricle:  for  this  purpose  open  its  cavity,  by  raising  the 
anterior  wall  in  the  form  of  a flap  from  below,  making  one  incision  along  its 
right  side,  and  the  other  near  the  septum  cordis.  The  right  ventricle  is  tri- 
angular, its  base  is  joined  to  the  auricle,  the  apex  is  a little  above  the  apex  of 
the  heart;  the  right  is  separated  from  the  left  ventricle  by  a thick  muscular 
lamina  (the  septum  cordis)  : the  parietes  of  this  cavity  are  rendered  very  ir- 
regular internally  by  numerous  muscular  projections,  the  cornese  column®  ; 
some  of  these  are  attached  throughout  their  whole  length,  others  are  fixed  by 
their  extremities,  and  loose  in  their  centre,  and  a third  species  are  fixed  by 
one  end  to  the  fleshy  substance  of  the  heart,  by  the  other  to  thin  tendinous 
cords  which  are  attached  to  the  auricular  valves ; the  carnese  column®  take 
various  directions,  and  are  all  covered  by  the  fine  lining  membrane  of  the 


44 


THE  DUBLIN  DISSECTOR, 


heart.  At  the  base  of  this  cavity  we  observe  the  auricular  and  arterial  open- 
ing, the  latter  is  superior,  anterior,  and  to  the  left  side  of  the  former;  from 
the  margin  of  the  auricular  opening  a fold  of  the  lining  membrane  descends 
into  the  ventricle,  the  inferior  loose  edge  of  which  divides  into  three  portions, 
each  ending  in  a very  irregularly  notched  margin,  to  which  the  chordae  ten- 
dineae  are  attached  ; these  are  the  tricuspid  valves,  one  division  is  anterior, 
the  second  is  posterior  on  the  septum  cordis,  and  the  third,  which  is  the 
largest,  is  to  the  left  side,  and  separates  the  auricular  from  the  arterial  open 
ing;  many  of  the  tendinous  threads  are  connected  to  the  dorsum,  as  well  a- 
to  the  edge  of  these  folds,  and  cross  each  other  as  they  run  to  the  carneae 
columnae.  The  use  of  the  tricuspid  valves  is  to  prevent  the  reflux  of  the 
blood  from  the  ventricle  into  the  auricle  ; as  the  former  cavitv  is  bein»  dis- 
tended,  the  blood  separates  the  valves  from  the  parietes  of  the  ventricle,  and 
thus  becomes  situated  on  their  outer  side;  when  the  ventricle  then  contracts, 
it  presses  the  blood  against  these  folds,  which  are  thus  approximated  to  each 
other,  and  slightly  raised  against  the  opening  so  as  to  close  it,  the  carnese 
columnae  at  the  same  time  contracting  make  tense  the  chordae  tendineae,  and 
thus  accomplish  the  two  objects,  1st,  of  completely  approximating  the  valves ; 
and  2d,  of  preventing  their  being  reversed  or  thrown  up  into  the  auricle.  The 
orifice  of  the  pulmonary  artery  is  small,  and  situated  at  the  highest  point,  and 
at  the  left  extremity  of  the  ventricle,  the  surface  of  which  becomes  smooth 
as  it  approaches  it ; this  vessel  is  connected  to  the  ventricle  by  the  external 
and  internal  serous  membranes  of  the  heart,  between  which  its  fibrous  coat 
is  connected  to  the  fleshy  fibres  of  the  ventricle  by  three  roots,  convex 
towards  the  heart,  and  marked  internally  each  by  a distinct  white  line  ; from 
this  arterial  opening  three  folds,  the  semilunar  valves,  extend  into  the  vessel, 
the  convex  edge  of  each  is  fixed  to  the  white  line  at  each  of  the  roots  of  the 
artery  ; the  concave  is  loose,  but  thick,  and  contains  in  its  centre  a small 
tubercle,  the  corpus  arantii,  or  sesamoideum.  The  use  of  these  valves  is  to 
prevent  the  blood  returning  from  the  artery  into  the  ventricle,  for,  as  the 
former  becomes  distended,  the  blood  flows  behind  these  valves,  separates 
them  from  the  sides  of  the  artery,  and  so  approximates  them  to  each  other  ; 
and  when  the  artery  contracts,  it  presses  the  blood  so  strongly  against  these 
valves  as  nearly  to  intercept  the  opening,  and  cause  the  blood  to  flow  onwards 
through  the  artery  ; the  corpora  arantii  are  supposed  to  be  of  use  in  giving 
additional  strength  towards  the  centre  of  the  opening,  where  the  pressure 
will  be  greatest;  the  semilunar  valves,  both  in  the  pulmonary  artery  and  in 
the  aorta,  while  they  support  the  column  of  blood  in  these  vessels  cannot 
wholly  prevent  its  regurgitation  to  the  heart.  The  pulmonary  artery  ascends 
obliquely  backwards  for  about  two  inches  and  a half  within  the  pericardium  ; 
and  just  as  it  escapes  from  this  cavity  it  divides  into  the  right  and  left  branch  : 
in  this  course  it  lies  at  first  anterior  to  the  aorta,  and  afterwards  to  the  left 
side.  The  right  pulmonary  artery  is  the  longer  branch ; it  turns  in  a trans- 
verse direction  to  the  right  side,  and  passes  through  the  arch  of  the  aorra,  and 
behind  the  superior  cava,  to  the  root  of  the  right  lung,  and  there  divides  into 
three  branches.  The  left  pulmonary  artery  is  short,  proceeds  to  the  left  side, 
and  entering  the  root  of  the  left  lung  anterior  to  the  left  bronchus,  divides 
into  two  branches  ; from  the  division  of  the  pulmonary  artery  a ligamentous 


OR  MANUAL  OF  ANATOMY. 


45 


cord  extends  backward  and  downwards  to  the  lower  extremity  of  the  arch  of 
the  aorta;  this  is  the  remains  of  the  ductus  arteriosus,  which  in  the  foetus 
conveyed  the  blood  from  the  pulmonary  artery  into  the  aorta,  as  it  could  not 
pass  in  any  quantity  through  the  condensed  structure  of  the  lungs ; the  re- 
current, or  inferior  laryngeal  nerve  of  the  left  side  winds  round  this  substance. 
In  the  lungs  the  pulmonary  arteries  divide  into  numerous  branches,  which 
spread  minutely  on  the  air-cells,  on  which  they  terminate  in  the  pulmonary 
veins,  which  vessels  thus  arise  by  innumerable  ramifications ; these  unite 
with  each  other,  and  form  larger  trunks,  which  arrive  at  the  root  of  the  lungs, 
two  on  each  side,  where  they  lie  anterior  and  inferior  to  the  pulmonary  artery ; 
these  veins  then  pass  inwards  to  join  the  left  auricle,  a cavity  which  may  be 
next  examined.  The  [eft  auricle  is  situated  at  the  upper  and  back  part  of  the 
heart,  in  front  of  the  mediastinum  ; it  may  be  exposed,  either  by  raising  the 
apex  of  the  heart,  or  removing  this  organ  from  the  body,  and  placing  it  on  its 
anterior  surface;  it  is  somewhat  square,  smaller  than  the  right,  but  its 
parietes  are  thicker  and  stronger;  from  its  upper  and  left  extremity  its  ap- 
pendix, which  is  very  small,  passes  forwards,  and  overlaps  the  origin  of  the 
pulmonary  artery;  lay  open  this  cavity  by  a perpendicular  incision  along  its 
middle  line  ; internally  we  perceive  it  smooth,  except  in  the  appendix,  where 
a few  fleshy  fasciculi  appear,  as  in  the  right  side  ; on  the  septum  auricularum, 
a slight  depression,  not  so  distinct  as  that  in  the  right  auricle,  marks  the 
former  situation  of  the  foramen  ovale  ; the  four  pulmonary  veins  are  seen 
opening  into  the  angles  of  this  cavity,  two  on  each  side ; those  of  the  left 
open  very  near  each  other,  and  sometimes  in  common,  beneath  the  opening  of 
the  appendix  ; at  its  inferior  part  we  perceive  the  opening  into  the  left  ven- 
tricle, circular,  smooth,  and  marked  by  a white  line,  as  in  the  right  auricula- 
ventricular  opening,  than  which  this  of  the  left  side  is  somewhat  smaller. 
The  left  ventricle  is  conical ; its  apex  forms  the  apex  of  the  heart ; flattened 
anteriorly  ; longer  but  smaller  than  the  right  ventricle ; its  parietes  are  much 
thicker,  and  to  it  the  septum  cordis  appears  to  belong : continue  the  incision 
that  had  been  made  in  the  left  auricle  downwards  along  the  back  of  the  left 
ventricle  to  its  apex ; the  great  thickness  of  its  walls,  and  the  roughness  of 
its  internal  surface  from  the  strong  and  projecting  carneae  columns,  may  now 
be  remarked;  at  the  superior  part  of  this  cavity  we  find  the  auricular  and 
aortic  openings  ; these  lie  very  near  each  other,  the  arterial  being  imme- 
diately in  front  of  the  auricular : from  the  circumference  of  the  latter  there 
descends  a fold  of  membrane,  which  divides  into  two  portions,  called  the 
mitral  valves ; these  are  stronger,  but  in  every  other  respect  are  similar  to  the 
tricuspid  valves  in  the  right  ventricle;  these  also  answer  a similar  office,  that 
of  preventing  the  blood  returning  from  the  left  auricle.  The  aortic  opening 
is  situated  at  the  upper  and  anterior  part  of  the  left  ventricle,  in  front  of  the 
auricular,  from  which  it  is  separated  by  the  anterior  or  large  division  of  the 
mitral  valve;  the  ventricle  is  smooth  in  the  vicinity  of  this  opening.  The 
anterior  division  of  the  mitral,  and  the  left  of  the  tricuspidal  valves  are  sup- 
posed to  be  larger  than  the  other  portions,  for  the  purpose  of  preventing  any 
blood  flowing  from  the  auricle  or  ventricle  into  the  aorta  or  pulmonary  artery 
until  the  ventricle  is  fully  distended.  The  aorta  arises  from  the  left  ven- 
tricle in  the  same  manner  as  the  pulmonary  artery  from  the  right ; three 
semilunar  valves  also  proceed  from  this  orifice  into  the  aorta,  stronger,  but 


46 


THE  DUBLIN  DISSECTOR, 


similar  in  structure  and  in  function  to  those  in  the  pulmonary  artery,  the  cor- 
pora arantii  in  particular  are  larger  and  firmer  in  the  aortic  valves ; external  to 
each  semilunar  valve,  the  aorta  is  dilated  into  a «mall  sinus;  these  three  are 
named  the  sinuses  of  Morgagni,  or  lesser  sinuses  of  the  aorta.  The  aorta  at  its 
origin  is  covered  by  the  pulmonary  artery;  it  ascends  obliquely  forwards  and 
to  the  right,  as  high  as  on  a level  with  the  cartilages  of  the  2d  rib  of  each  side ; 
it  then  passes  backwards,  and  to  the  left  side;  and  lastly  descending  as  low 
as  the  4th  dorsal  vertebra,  it  becomes  closely  attached  to  the  spine : this  por- 
tion of  the  aorta  is  called  the  arch,  at  the  termination  of  which  this  vessel 
receives  the  name  of  thoracic  or  descending  aorta,  which  descends  through 
the  posterior  mediastinum,  as  was  already  stated  ; the  arch  of  the  aorta  is  di- 
vided into  the  ascending,  the  transverse,  and  the  descending ; the  first  is  the 
longest  portion,  and  in  general  is  so  much  dilated  at  the  upper  part  as  to  have 
received  the  name  of  the  great  sinus ; this  ascending  portion  is  within  the 
pericardium,  covered  at  first  by  the  pulmonary  artery  ; it  afterwards  lies  be- 
tween this  vessel  and  the  vena  cava ; from  the  commencement  of  this,  the 
two  coronary  arteries  arise;  the  middle  or  transverse  portion  of  the  arch 
lies  above  the  pericardium,  and  in  front  of  the  trachea;  from  it  arise  the  ino- 
minata,  left  carotid  and  left  subclavian  ; the  descending  portion  bends  behind 
the  root  of  the  left  lung,  and  is  connected  to  the  pulmonary  artery  by  the 
remains  of  the  ductus  arteriosus  ; through  the  arch  of  the  aorta,  the  right 
pulmonary  artery,  left  bronchus  and  left  recurrent  nerve  pass. 

The  heart  is  composed  of  three  tunics:  1st,  the  reflected  serous  layer  of 
the  pericardium,  externally;  2d,  the  serous  membrane  which  lines  the  vascular 
system,  internally  ; and  3dly,  between  these  membranes  a lamina  of  muscular 
substance  : the  serous  membranes  are  stronger,  but  the  muscular  tunic  weaker 
in  the  auricles  than  in  the  ventricles  ; the  muscular  fibres  are  arranged 
chiefly  in  a spiral  direction,  but  they  are  so  closely  united  that  their  course  is 
not  obvious,  unless  after  long  maceration ; external  to  this  tunic,  in  the  adult 
or  old,  and  on  the  right  side  principally,  we  generally  find  a quantity  of  adeps 
placed.  The  coats  of  the  heart  are  supplied  with  blood  from  the  two  coronary 
arteries,  the  first  branches  of  the  aorta  : the  nerves  of  the  heart  are  small  and 
numerous,  they  are  derived  from  the  cervical  ganglions  of  the  sympathetic, 
and  from  the  pneumo-gastric  of  each  side.  (See  Vascular  and  Nervous  Sys- 
tems.)— The  student  may  next  examine  what  are  the  parts  which  pass  through 
the  upper  orifice  of  the  thorax. 

Posterior  to  the  deep  cervical  fascia  we  perceive  the  sterno-hvoid  and  thy- 
roid muscles  first  ascending  through  this  opening:  behind  these  is  a quantity 
of  cellular  membrane,  and  the  remains  of  the  thymus  gland : next  are  the  right 
and  left  vense  innominatae,  the  former  descending  perpendicularly,  the  latter 
obliquely  across  this  opening  ; these  two  veins  unite  opposite  the  cartilage  of 
the  2d  rib  of  the  right  side,  and  form  the  superior  vena  cava,  which  soon  enters 
the  pericardium,  and  empties  itself  into  the  right  auilcle;  behind  these  veins, 
the  phrenic  and  par  valgum  enterthe  chest;  the  former  is  external  and  anterior 
to  the  latter,  and  both  are  anterior  to  the  subclavian  arteries.  The  phrenic 
nerve,  accompanied  by  the  internal  mammary  vessels,  descends  through  the 
thorax,  anterior  to  the  root  of  the  lungs,  to  the  diaphragm,  to  which  it  is  dis- 
tributed; this  nerve  on  the  left  side  is  longer,  and  lies  somewhat  posterior  to 
that  on  the  right  side  ; the  8th  pair  entering  the  chest,  between  the  subclavian 


OR  MANUAL  OF  ANATOMY. 


47 


vein  and  artery,  passes  backwards  behind  the  root  of  the  lung,  on  which  it 
forms  an  extensive  plexus,  pulmonary  plexus ; it  then  enters  thq  posterior 
mediastinum,  and  becomes  attached  to  the  oesophagus,  which  conducts  it  to 
the  stomach.  We  next  perceive  the  innominata,  left  carotid,  and  left  sub- 
clavian arteries  ascending  out  of  this  cavity  ; the  innominata  is  most  anterior, 
and  the  left  subclavian  the  most  posterior  of  the  three.  The  trachea  is  next 
seen  entering  the  thorax,  behind  these  vessels,  and  inclining  a little  to  the  right 
side  ; this  tube  commences  opposite  the  5th  or  6th  cervical  vertebra,  descends 
at  first  in  the  middle  line,  but  as  it  approaches  the  chest,  it  inclines  to  the 
right,  aorta  pressing  on  its  left  side ; in  the  neck  it  rests  on  the  oesophagus, 
and  lies  between  the  great  vessels;  it  is  covered  by  the  thyroid  gland  and  its 
veins,  the  sternal  muscles,  the  arteria  and  left  vena  innominata:  in  the  thorax, 
the  trachea  descends  obliquely  backwards,  and  opposite  the  3d  dorsal  vertebra 
it  divides  into  the  right  and  left  bronchial  tubes  ; a number  of  dark  lymphatic 
glands  (the  bronchial  glands)  lie  in  the  angle  of  the  division,  and  adhere  closely 
to  the  branches.  The  trachea  is  composed  of  18  or  20  fibro  cartilages,  con- 
nected together  by  an  elastic  substance,  and  lined  by  mucous  membrane  ; each 
cartilage  forms  about  three-fourths  of  a circle,  the  deficiency  posteriorly  being 
filled  by  a fibrous  membrane,  which  also  encloses  the  cartilages,  and  by  some 
transverse  muscular  fibres  and  mucous  glands;  the  right  bronchial  tube  is  the 
larger  branch  ; it  runs  transversely  into  the  root  of  the  lung,  and  divides  into 
three  branches  ; the  vena  azygos  bends  over  this  vessel ; the  left  bronchial 
tube  is  longer,  and  takes  a course  slightly  curved  downwards  and  to  the  left 
side,  through  the  arch  of  the  aorta  to  the  root  of  the  left  lung,  and  then  divides 
into  two  branches;  the  further  subdivisions  of  these  two  tubes  gradually  lose 
the  cartilaginous  structure,  divide  into  numerous  fine  membranous  vessels, 
which  terminate  in  small  cells ; these  communicate  with  each  other,  and  on 
these  the  pulmonary  vessels  minutely  ramify : the  bronchi  are  composed  of 
the  same  structures  as  the  trachea,  the  cartilages,  however,  soon  lose  their 
annular  form,  and  become  irregular ; in  their  minute  subdivisions  they  no 
longer  exist ; the  air  serves  to  retain  these  as  well  as  the  cells  in  a perma- 
nently distended  condition.  Behind  the  trachea,  the  oesophagus  is  seen  en- 
tering the  thorax,  lying  close  to  the  spine;  at  first  a little  to  the  left  of  the 
mesial  line,  afterwards  to  the  right  of  that  line,  and  as  it  descends  through 
the  posterior  mediastinum,  it  again  inclines  to  the  left.  On  the  left  side  of 
this  tube,  the  thoracic  duct  is  seen  ascending  from  the  thorax  into  the  neck, 
between  the  left  carotid  and  subclavian  arteries.  As  the  oesophagus  enters 
the  chest,  we  observe  on  either  side  of  it  the  recurrent  nerve  ; that  of  the  left 
side  passes  out  of  this  cavity,  that  of  the  right  arises  on  a level  with  this  opening : 
external  to  this  nerve,  on  each  side,  we  perceive  the  sympathetic  entering  the 
chest ; it  lies  posterior  to  the  phrenic  and  the  vagus,  but  between  both  ; this 
nerve  having  formed  its  inferior  cervical  ganglion,  divides  into  several  branches 
which  descend  into  the  thorax,  a few  pass  anterior  to  the  subclavian  artery, 
the  principal  pass  behind  it ; they  all  unite  in  its  first  thoracic  ganglion,  which 
is  situated  on  the  neck  of  the  first  rib;  the  sympathetic  then  descends  along 
the  side  of  the  spine,  passing  over  the  heads  of  the  ribs,  and  opposite  each  in- 
tercostal space  forms  a small  triangular  ganglion,  from  each  of  which  two  or 
three  small  branches  proceed  to  join  the  dorsal  spinal  nerves,  and  from  the 
five  or  six  inferior  the  great  and  small  splanchnic  nerves  arise ; the  sympa- 


48 


THE  DUBLIN  DISSECTOR, 


thetic  is  so  small,  inferiorly,  that  it  is  often  difficult  to  trace  it ; it  escapes 
from  the  thorax  into  the  abdomen,  beneath  the  true  ligamentum  arcuatum. 
Posterior  to  the  oesophagus,  the  longi  colli  muscles  ascend  through  the  upper 
opening  of  the  thorax;  on  each  side  of  these  lie  the  superior  intercostal  artery, 
and  the  anterior  branch  of  the  1st  dorsal  nerve,  ascending  to  join  the  last 
cervical  in  the  brachial  plexus. 


CHAPTER  IV. 

§ 1 . — Muscles  of  the  Buck. 

Place  the  subject  on  the  forepart,  raise  the  chest  by  blocks,  let  the  head 
and  arms  hang,  thus,  the  muscles  in  this  region  will  be  made  tense  : divide 
the  integuments  along  the  middle  line,  from  the  occiput  to  the  sacrum  ; make 
a transverse  incision  from  the  last  cervical  vertebra  to  the  acromion,  and 
another  from  the  last  dorsal  vertebra  to  the  posterior  part  of  the  axilla;  re- 
flect the  upper  and  lower  flap  of  integument  from  the  spine  towards  the  side 
and  raise  the  middle  portion  from  below  upwards  and  inwards  ; thus  the  dis- 
sector can  most  easily  expose  the  trapezius  andlatissimus  dorsi  muscles  ; the 
integuments  in  this  region  are  dense,  also  the  subjacent  cellular  tissue,  which 
seldom  contains  much  adeps,  inferiorly  it  is  often  anasarcous;  when  all  this 
is  dissected  from  the  posterior  part  of  the  trunk,  we  see  exposed  the  trapezius 
superiorly,  the  latissimus  dorsi  inferiorly, and  between  these,  in  a small  trian- 
gular space  behind  the  base  of  the  scapula,  a part  of  the  great  rhomboid,  also 
two  or  three  tendons  of  the  sacro-lumbalis,  and  a portion  of  the  7th,  8th,  and 
9th  ribs,  and  of  the  corresponding  intercostal  muscles;  along  the  middle  line 
of  the  neck  a strong  ligament  in  observed,  (ligamentum  nuchae),  at  the  lower 
part  of  which  a strong  aponeurosis  of  an  oval  form  (the  cervical  aponeurosis)  : 
also  covering  the  lumbar  region  another  still  stronger  is  seen,  (the  lumbar 
fascia) : to  each  of  these  the  student  should  pay  attention.  The  ligamentum 
nuchas  is  inserted  superiorly  into  the  occipital  protuberance,  it  descends  in  the 
median  line,  broad  above,  and  sinking  in  deep,  so  as  to  form  a septum  between 
the  muscles  on  the  right  and  left  sides  and  is  inserted  inferiorly  into  the  spinous 
processes  of  the  three  or  four  last  cervical  vertebrae,  and  into  the  cervical  apon- 
eurosis. Use,  to  support  the  thead  in  flexion  of  the  neck,  and  to  give  attach- 
ment to  muscles.  The  cervical  aponeurosis  extends  from  the  5th  cervical  to 
the  5th  dorsal  vertebra,  narrow  at  each  extremity,  and  broad  in  the  centre 
between  the  superior  angles  of  the  two  scapulae ; the  fibres  are  transverse,  and 
continuous  with  the  fibres  of  the  trapezius  on  each  side  : it  gives  strength  to 
these,  and  binds  down  the  subjacent  muscles.  The  lumbar  fascia  is  of  great 
strength;  it  is  also  somewhat  oval,  attached  by  its  inferior  extremity  to  the 
spinous  processes  of  the  sacrum,  and  by  its  superior  to  those  of  the  inferior 
dorsal  vertebrae;  on  either  side  it  is  connected  to  the  crest  of  the  ilium,  and 
to  the  abdominal  muscles,  particularly  to  the  transversalis,  also  to  the  latissi- 
mus dorsi  and  seratus  posticus  inferior ; its  internal  surface  is  attached  along 
the  median  line  to  the  spines  of  the  lumbar  vertebrae,  and  on  either  side  to  the 
transverse  processes.  This  fascia  gives  great  support  to  the  loins,  where  the 
skeleton  is  comparatively  weak ; like  the  ligamentum  nuchae  it  supports  the 


OR  MANUAL  OF  ANATOMY. 


49 


trunk  in  flexion,  it  also  assists  in  maintaining  itinequilibrioin  lateral  motion, 
and  it  also  serves  to  give  attachment  to  several  muscles,  which  again  in  their 
turn  serve  to  keep  it  in  a state  of  tension. 

The  muscles  of  the  back  are  many  of  them  indistinct  and  vary  very  much 
in  different  subjects  both  in  their  appearance  and  in  their  exact  attachments 
to  any  certain  number  of  vertebrae ; the  student  is  not  to  expect  therefore  to 
find  each  muscle  in  this  region  to  correspond  accurately  with  the  description 
that  is  given,  some  being  attached  to  a greater,  others  to  a lesser  number  of 
processes  than  is  stated.  The  muscles  of  the  back  are  arranged  in  four  suc- 
cessive layers,  each  nearly  covering  the  other  between  the  integuments  and 
the  bones ; the  muscles  of  the  first  layer  are  the  trapezius  and  the  latissimus 
dorsi. 

Trapezius,  broad,  triangular,  the  base  along  the , spine,  the  apex  at  the 
shoulder,  arises  by  a thin  aponeurosis  from  the  internal  third  of  the  superior 
transverse  ridge  of  the  occipital  bone,  from  the  ligamentum  nuchse,  and  from 
the  spinous  processes  of  the  last  cervical,  and  of  all  the  dorsal  vertebrae;  the 
superior  fibres  descends  obliquely  outwards  and  forwards ; the  middle  pass 
transversely,  the  inferior  ascend  obliquely  forwards ; all  converge  towards 
the  shoulder,  and  are  inserted  into  the  posterior  border  of  the  external  third 
of  the  clavicle,  and  of  the  acromion  process,  also  into  the  upper  edge  of  the 
spine  of  the  scapula.  Use,  to  raise  and  draw  backwards  the  shoulder ; the 
inferior  fibres  which  end  in  a triangular  shaped  tendon,  which  glides  over  the 
triangular  smooth  surface  at  the  commencement  of  the  spine,  may  draw  down 
the  base  of  the  scapula,  and  thus  by  rotating  this  bone  will  elevate  the  acro- 
mion process  and  assist  the  remainder  of  the  muscle  in  raising  the  shoulder; 
the  trapezius  may  also  incline  the  head  backwards  and  to  one  side.  This  muscle 
is  covered  by  the  skin  only,  its  origin  in  many  points  is  continuous  with  that  of 
its  fellow;  it  covers  the  splenii,  complexi,serratus superior,  levator  scapulae, 
and  rhomboid  muscles ; its  anterior  fibres  are  parallel  to  the  sterno-mastoid,  in 
contact  with  it  above,  but  separated  below,  by  fat,  vessels  and  nerves;  in 
some  subjects  a band  of  fleshy  fibres  unites  these  muscles  above  the  clavicle. 

Latissimus  Dorsi  is  very  broad,  and  also  triangular  ; it  covers  the  greater 
part  of  the  lumbar  and  dorsal  regions,  and  extends  from  these  to  the  inner 
side  of  the  arm;  arises  from  the  six  inferior  dorsal  spines,  and  by  the  lum- 
bar fascia  from  all  the  lumbar  spines,  also  from  the  back  of  the  sacrum,  from 
the  posterior  third  of  the  crest  of  the  ilium,  and  by  distinct  fleshy  slips  from 
the  three  or  four  last  ribs  near  their  anterior  extremity  ; the  iliac  and  lum- 
bar fibres  ascend  obliquely  outwards ; the  dorsal,  which  are  much  weaker,  pass 
transversely;  and  the  costal  are  nearly  vertical;  all  converge  towards  the 
inferior  angle  of  the  scapula,  over  which  they  glide,  and  from  which  they  of- 
ten derive  an  additional  fasciculus  of  fleshy  fibres  ; thence  the  muscle  continues 
to  ascend  obliquely  outwards  over  the  teres  major,  and  near  the  inside  of  the 
arm  it  twist  beneath  this  muscle  to  its  forepart,  ends  in  a flat  broad  tendon, 
which  is  closely  connected  to  that  of  the  teres,  and  is  inserted  into  the  inner 
or  posterior  edge  of  the  bicipital  groove,  anterior  and  superior  to  that  tendon  ; 
a small  bursa  is  usually  found  between  these  tendons  in  this  situation.  Use, 
to  depress  the  shoulder  and  arm,  to  draw  the  arm  backwards  and  inwards,  to 
rotate  the  humerus  inwards,  so  as  to  turn  the  palm  of  the  hand  backwards, 
also  to  depress  the  ribs  as  in  expiration : but  if  the  upper  extremity  be  raised 
7 


50 


THE  DUBLIN  DISSECTOR, 


and  fixed,  this  muscle  may  elevate  the  ribs,  and  so  assist  in  inspiration,  as 
well  as  in  raising  the  whole,  as  in  climbing. 

The  dorsal  portion  of  the  latissimus  dorsi  is  covered  by  the  trapezius  ; the 
remainder  of  this  muscle  is  superficial,  its  origin  is  superior  to  the  glutaeus 
maximus,  its  anterior  edge  is  connected  to  the  abdominal  muscles,  the  inferior 
faciculi  of  the  external  oblique  indigitate  with  its  costal  origins;  it  covers 
the  serratus  inferior,  the  lumbar  muscles,  and  the  angle  of  the  scapula  ; its  hu- 
meral end  forms  the. posterior  fold  of  the  axilla;  a fasciculus  of  fleshy  fibres 
sometimes  passes  across  the  floor  of  this  region,  and  connects  the  latissimus 
to  the  great  pectoral  muscle ; between  the  angle  of  the  scapula  and  the  hu- 
merus, this  muscle  has  a twisted  appearance,  the  lumbar  and  costal  fibres 
being  inserted  into  the  upper  part  of  the  tendon,  and  the  superior  or 
dorsal  portion  into  its  inferior  edge ; the  axillary  vessels  and  nerves  lie  on 
this  tendon  at  its  insertion,  and  the  bicipital  groove  is  lined  by  aponeurotic 
fibres  derived  from  it,  and  from  the  tendon  of  the  great  pectoral,  which  are 
thus  united  to  each  other,  although  previous  to  this  they  are  separated  by  the 
brachial  vessels  and  nerves,  and  by  the  coraco-brachialis  and  biceps  muscles. 
Divide  the  trapezius  and  latissimus  longitudinally  between  the  spine  and 
the  scapula,  reflect  one  portion  towards  the  vertebrae,  the  other  towards 
the  side,  and  the  second  layer  of  the  dorsal  muscles  will  be  exposed.  (In 
dissecting  off  the  latissimus  take  care  not  to  injure  the  serratus  inferior,  which 
is  very  thin,  and  adheres  closely  to  it.) 

The  second  layer  of  muscles  consists  of  the  rhomboid,  levator  anguli  sca- 
pulae, serratus  inferior  and  superior,  and  the  splenii ; a considerable  portion  of 
each  of  these  is  now  seen,  although  they  partly  conceal  each  other. 

Rhomboideus  is  broad,  thin,  and  the  most  superficial  of  this  layer;  it  is 
divided  into  a superior  or  minor  portion,  and  an  inferior  or  major;  the  minor 
arises  from  the  lower  part  of  the  ligamentum  nuchae,  and  from  the  last  cervi- 
cal spinous  process;  the  fibres  run  parallel  outwards, and  a little  downwards, 
and  are  inserted  into  the  base  of  the  scapula,  opposite  to  and  above  the  spine. 
The  major  arises  from  the  four  or  five  superior  dorsal  spines  ; the  fibres  pass 
outwards  and  downwards  parallel  to  the  former  and  are  inserted  into  the  base 
of  the  scapula,  extending  from  the  spine  to  the  inferior  angle.  Use,  to  draw 
the  shoulder  backwards  and  upwards ; the  inferior  fibres  also  can,  by  pulling 
back  the  inferior  angle,  rotate  the  scapula,  so  as  to  depress  the  acromion  pro- 
cess. The  rhomboid  muscles  are  covered  by  the  trapezius,  latissimus,  and 
integuments,  and  conceal  part  of  the  serrati  postici  muscles. 

Levator  Anguli  Scapulae,  long,  and  somewhat  round,  placed  at  the  upper 
and  posterior  part  of  the  side  of  the  neck,  arises  by  four  on  five  tendons  from 
the  posterior  tubercles  of  the  transverse  processes  of  the  four  or  five  superior 
cervical  vertebrae;  these  soon  terminate  in  a fleshy  belly,  which  descends  ob- 
liquely outwards  and  backwards,  and  is  inserted  into  the  base  of  the  scapula, 
between  the  spine  and  superior  angle  ; its  use  is  to  elevate  the  whole  scapula, 
if  assisted  by  the  trapezius,  or  to  elevate  the  superior  angle  alone,  and  to  ro- 
tate the  scapula  so  as  to  depress  the  acromion,  thus  co-operating  with  the  lesser 
pectoral  muscle  ; it  is  covered  by  the  trapezius;  a small  portion  may  be  seen 
superiorly  between  this  and  the  sterno-mastoid  muscle  ; the  tendinous  origins 
have  those  of  the  splenius  colli  behind  them,  and  of  the  scaleni  and  rectus 
capitis  anticus  major  before  them.  Divide  and  reflect  the  rhomboid  muscles ; 


OR  MANUAL  OF  ANATOMY. 


51 


beneath  these  a quantity  of  loose  cellular  membrane  is  placed,  between  them 
and  the  serratus  magnus,  to  the  posterior  view  of  which  muscle  the  student 
should  now  attend ; he  may  therefore  again  peruse  the  account  given  of  that 
muscle  (see  page  55). 

Serratus  Posticus  Superior,  arises  by  a thin  aponeurosis  from  the  liga- 
mentum  nuchae,  and  from  two  or  three  dorsal  spines,  forms  a thin  fleshy  belly 
which  ends  in  three  fleshy  slips,  which  are  inserted  into  the  2d,  Sd,  and  4th  ribs 
external  to  their  angles.  Use,  to  expand  the  thorax  by  elevating  the  ribs  and 
drawing  them  outwards.  This  muscle  is  covered  by  the  trapezius  and  rhom- 
boid ; it  lies  on  the  splenius  and  the  deep  layer  of  muscles ; an  aponeurosis  is 
continued  from  it  to  the  inferior  serratus. 

Serratus  Posticus  Inferior,  arises  by  a thin  tendinous  expansion,  wbich'is 
connected  through  the  lumbar  fascia  to  the  two  last  dorsal  and  two  upper  lum- 
bar spines;  it  forms  a thin  fleshy  expansion,  which  divides  into  three  or  four 
fasciculi,  which  are  inserted  into  the  lower  edge  of  the  four  inferior  ribs  ante- 
rior to  their  angles.  Use,  by  depressing  the  ribs  it  assists  the  abdominal 
muscles  in  expiration;  also,  by  fixing  the  lower  ribs  it  increases  the  power  of 
the  diaphragm,  and  by  aiding  this  muscle  in  enlarging  the  thorax  it  assists  in 
inspiration ; the  two  serrati  also,  by  making  tense  the  aponeurosis  which  con- 
nects them  to  each  other,  compress  and  support  the  deep  muscles  in  this  region  ; 
reflect  from  its  origin  the  superior  serratus,  and  we  shall  see  the  following 
muscle. 

Splenius,  is  long  and  flat,  fleshy  and  tendinous,  lying  beneath  the  trapezius, 
and  extending  in  an  oblique  direction  from  below,  upwards,  forwards  and  out- 
wards ; it  is  divided  into  two  portions,  the  inferior,  or  splenius  colli,  and  the 
superior  or  splenius  capitis.  The  splenius  colli  arises  from  the  spines  of  the 
3d,  4th,  5th,  and  6th  dorsal,  ascends  obliquely  outwards,  and  is  inserted  by 
distinct  tendons  into  the  transverse  processes  of  the  three  or  four  superior 
cervical  vertebras,  behind  the  origins  of  the  lavator  scapular.  Use,  to  bend  the 
neck  backwards,  and  to  one  side.  Splenius  capitis  is  larger  than  the  last,  superior 
and  internal  to  which  it  lies ; it  arises  from  the  spinous  processes  of  the  two 
superior  dorsal  and  three  inferior  cervical  vertebrae,  and  from  the  ligamentum 
nuchae  ; it  ascends  a little  obliquely  outwards,  and  becoming  larger,  is  inserted 
into  the  back  part  of  the  mastoid  process,  overlapping  the  sterno-mastoid,  and 
into  the  occipital  bone,  below  the  superior  transverse  ridge.  Use,  to  bend  back 
the  head  and  when  one  only  acts  to  turn  the  head  to  that  side ; thus  co-opera- 
ting with  the  sterno-mastoid  of  the  opposite  side. 

The  splenii  capitis  muscles  diverge  superiorly,  and  the  complexi  appear  be- 
tween them.  Detach  the  splenii  from  the  spinous  processes,  and  divide  the 
fascia  lumborum,  and  the  next  layer  of  muscles  will  appear;  this  consists  of 
the  sacro-lumbalis,  longissimus  dorsi  and  spinalis  dorsi,  cervicalis  descendens, 
tranversalis  colli,  trachelo-mastoideus  and  complexus. 

Sacro-lumbalis,  Longissimus  Dorsi,  and  Spinalis  Dorsi,  these  three  mus- 
cles are  so  closely  connected  interiorly  as  to  appear  but  one  mass,  and  several 
fibres  must  be  divided  in  order  to  separate  them  from  each  other.  Sacro-lum- 
balis is  the  largest  of  the  three  ; it  arises  from  the  posterior  third  of  the  crest 
of  the  ilium,  from  the  oblique  and  transverse  processes  of  the  sacrum,  from  the 
sacro-iliac  ligaments,  and  from  the  transverse  and  oblique  processes  of  the  lum- 
bar vertebrae ; it  ascends  and  divides  into  several  long  tendons,  which  are 


52 


THE  DUBLIN  DISSECTOR, 


inserted  into  all  the  ribs  near  their  angles.  Use , to  extend  the  spine,  and  bend 
it  a little  to  one  side,  also  to  depress  the  ribs  as  in  expiration.  The  longissimus 
dorsi  lies  internal  to  the  last,  and  arises  in  common  with  it,  from  the  posterior 
surface  of  the  sacrum  and  of  the  transverse  and  oblique  processes  of  the  lum- 
bar vertebrae  ascending  along  the  vertebral  column,  it  is  inserted  internallj  by 
small  tendons  into  all  the  dorsal  vertebrae,  and  externally  by  fleshy  and  ten- 
dinous slips  into  all  the  ribs  between  their  tubercles  and  angles.  Use , to  ex- 

tend, bend  to  one  side,  and  support  the  spinal  column.  When  we  separate 
the  sacro-lumbalis  from  the  longissimus  dorsi  and  evert  the  former,  we  shall 
expose  five  or  six  small  tendinous  and  fleshy  fasciculi  which  arise  from  the 
superior  edge  of  each  rib,  and  ascending  are  inserted  into  the  tendons  of  the 
sacro-lumbalis ; these  are  called  the  musculi  accessorii ; they  are  very  irregular 
in  number,  structure  and  size.  Spinalis  dorsi  lies  between  the  longissimus 
dorsi  and  spine;  it  arises  from  the  two  superior  lumbar  and  three  inferior 
dorsal  spines;  it  ascends  close  to  the  spinal  column,  and  is  inserted  into  the 
nine  superior  dorsal  spines : its  use  is  similar  to  the  last.  These  three  muscles 
are  covered  by  the  lumbar  fascia,  and  by  the  two  preceding  layers.  These 
lumbar  muscles  in  old  subjects  will  be  often  found  soft,  weak,  and  pale,  and 
often  blended  with  a soft  fatty  substance,  so  as  sometimes  to  resemble  a mass 
of  adipocere. 

Cf.rvicalis  Descendens,  or  more  properly  Ascendens,  looks  like  a con- 
tinuation of  the  sacro-lumbalis,  internal  to  which  it  arises  by  four  or  five  ten- 
dons from  as  many  of  the  superior  ribs  between  their  tubercles  and  angles; 
these  unite  in  a small  fleshy  belly,  which  ascends  obliquely  forwards  and  out- 
wards, and  is  inserted  by  three  or  four  tendons  into  the  transverse  processes 
of  the  4th,  5th  and  6th  cervical  vertebrae,  between  the  splenius  colli  and  leva- 
tor scapulae.  Use,  to  extend  the  neck,  and  incline  or  turn  it  to  one  side;  it 
may  also  assist  in  inspiration  by  elevating  the  ribs. 

Transversalis  Colli,  appears  as  a prolongation  of  the  longissimus  dorsi, 
internal  to  which  it  arises  by  small  tendinous  and  fleshy  slips  from  the  trans- 
verse processes  of  five  or  six  superior  dorsal  vertebrae;  the  fibres  uniting 
ascend  obliquely  outwards  and  forwards,  and  are  inserted  by  small  tendons 
into  the  transverse  processes  of  three  or  four  inferior  cervical  vertebrae  be- 
tween the  cervicalis  descendens  and  the  trachelo-mastoideus ; its  use  is  nearly 
similar  to  that  of  the  last  described  muscle. 

Trachelo  Mastoideus  lies  internal  to  the  last,  and  external  to  the  corn- 
plexus  ; it  arises  by  several  tendinous  bands  from  the  transverse  processes  of 
three  or  four  superior  dorsal  vertebras,  and  from  as  many  inferior  cervical ; 
ascending  a little  outward  it  is  inserted  into  the  inner  and  back  part  of  the 
mastoid  process  beneath  the  insertion  of  the  splenius.  Use,  to  assist  in  ex- 
tending the  neck,  to  bring  the  head  backwards,  and  to  incline  and  rotate  it  to 
one  side. 

Complexus  arises  from  the  transverse  and  oblique  processes  of  three  or 
four  inferior  cervical,  and  five  or  six  superior  dorsal  vertebrae,  internal  to  the 
transversalis  and  trachelo-mastoideus;  it  forms  a very  thick  muscle  inter- 
sected by  many  tendinous  bands;  it  ascends  a little  inwards,  and  is  inserted 
close  to  its  fellow  into  the  occipital  bone,  between  the  two  transverse  ridges. 
Use,  to  draw  back  the  head,  to  fix  and  support  it  on  the  spine,  also  to  rotate 
it,  be:;ig,  in  this  action,  an  antagonist  to  the  splenius,  and  an  auxiliary  to  the 


OR  MANUAL  OF  ANATOMY. 


53 


sterno-mastoid  of  its  own  side.  The  complexus  is  concealed  by  the  trapezius 
and  splenius ; its  insertion,  which  is  covered  by  the  former  only,  can  be  felt 
and  seen  through  the  integuments ; it  lies  on  the  semi-spinalis  colli,  the  deep 
cervical  artery,  and  the  small  oblique  and  recti  muscles.  Detach  the  com- 
plexus from  the  spine  and  reflect  it  towards  the  occiput,  and  evert  towards 
the  ribs  the  other  muscles  of  this  layer,  we  shall  thus  expose  the  fourth  layer 
of  the  dorsal  muscles,  which  consists  of  the  spinalis  or  semi-spinalis  colli,  the 
semi-spinalis  dorsi,  multifidus  spinae,  inter-spinalis,  inter-transversales,  and 
immediately  below  the  occiput,  of  the  recti  postici,  major  and  minor,  and 
obliqui  capitis,  superior  and  inferior. 

Spinalis  Colli,  arises  from  the  extremity  of  the  transverse  processes  of 
five  or  six  superior  dorsal  vertebrae,  ascends  obliquely  inwards,  and  is  inserted 
by  four  heads  into  the  spinous  process  of  the  2d,  3d,  4th  and  5th  cervical  ver- 
tebrae. Use,  to  extend  the  neck  and  incline  it  a little  to  its  own  side:  this 
thick  muscle  fills  up  the  space  between  the  spinous  and  transverse  processes 
of  the  cervical  and  dorsal  vertebrae : it  lies  external  to  the  semi-spinalis  dorsi, 
is  overlapped  by  the  longissimus  dorsi  interiorly,  the  complexus  superiorly, 
and  the  serratus  posticus  superior  in  the  middle. 

Semi-Spinalis  Dorsi  is  similar  to  the  last  muscle  in  form  and  attachment; 
indeed  they  appear  as  one  long  muscle,  which  has  been  thus  rather  unneces- 
sarily divided  into  two,  each  named  from  the  situation  of  its  principal  portion ; 
it  arises  by  five  or  six  tendons  from  the  transverse  processes  of  the  dorsal 
vertebrae,  from  the  5th  to  the  11th;  its  fibres  ascend  obliquely  inwards,  and 
are  inserted  by  five  or  six  tendons  into  the  extremity  of  two  inferior  cervical, 
and  three  or  four  superior  dorsal  vertebrae.  Use,  co-operates  with  the  last 
described  muscle,  in  extending  the  neck,  supporting  the  trunk,  and  inclining 
the  spine  backwards,  and  to  one  side : it  is  situated  close  to  the  spine  above, 
and  internal  to  the  last  muscle ; but  below,  it  lies  on  the  outer  side  of  the 
spinalis  dorsi. 

Multifidus  Spina:  is  close  to  the  vertebrae,  between  the  spinous  and  trans- 
verse processes,  and  is  covered  by  the  two  last  described  muscles;  it  consists 
of  a series  of  small  tendinous  and  fleshy  fasciculi ; th e first  arises  from  the 
spine  of  the  dentatus,  or  2d  vertebra,  and  descending  obliquely  outwards,  is 
inserted  into  the  transverse  process  of  the  3d : thus  the  succeeding  muscles 
are  attached,  running  obliquely  from  vertebra  to  vertebra  between  their  spinous 
and  transverse  processes ; some  fasciculi  extend  over  two  or  three  vertebrae: 
the  last  arises  from  the  spine  of  the  last  lumbar  vertebra,  and  is  inserted  into 
the  false  transverse  process  of  the  sacrum.  Use,  to  support  the  spinal  column, 
extend  it,  and  incline  it  to  one  side,  and  to  rotate  one  bone  upon  the  other,  as 
far  as  their  articulating  surfaces  will  admit. 

Inter-spinales  are  short  muscles,  consisting  of  longitudinal  fibres  ; their 
name  expresses  their  situation  and  attachment ; between  the  cervical  spines 
they  are  more  distinct,  and  appear  to  be  in  pairs,  right  and  left,  as  the  spinous 
processes  here  are  forked  ; some  fibres  in  the  neck  deserve  the  name  of  supra- 
spinous muscles,  as  they  pass  over  these  processes,  cover  and  adhere  to  seve- 
ral of  them : in  the  back  they  are  very  indistinct,  almost  wanting,  and  in  the 
loins  they  are  much  weaker  than  in  the  neck,  chiefly  consisting  of  ligamen- 
tous fibres,  with  a few  muscular  intermixed.  Use,  to  support  and  extend  the 
spine.  ui  < 


54 


THE  DUBLIN  DISSECTOR, 


Inter-transversales  consist  of  longitudinal  fibres  attached  and  situated, 
as  their  name  implies ; between  the  cervical  vertebrae  these  muscles  are  more 
strong  and  distinct,  and  consist  of  two  planes,  an  anterior  and  posterior ; 
between  the  lumbar  vertebrae  they  are  less  distinct;  and  still  less  so,  indeed 
often  wanting,  between  the  dorsal.  Use,  to  support  the  spine  on  either  side, 
and  to  bend  it  laterally.  External  to  these  in  the  back,  the  levatorescostarun 
muscles  are  seen,  which  have  been  already  noticed  in  the  description  of  the 
intercostals.  Between  the  occiput  and  the  first  vertebrae,  the  following  four 
pair  of  muscles  are  situated. 

Rectus  Capitis  Posticus  Major.  Triangular;  arises  narrow  from  the 
spinous  process  of  the  2d  vertebra;  ascends  outwards,  and  is  inserted  broad 
into  the  inferior  transverse  ridge  of  the  occipital  bone.  Use,  to  extend  the 
head,  or  draw  it  backwards,  also  to  rotate  it  and  the  atlas  on  the  dentatus, 
co-operating  with  the  splenius  of  the  same  side ; this  muscle  is  covered  by 
the  complexus ; its  insertion  is  overlapped  by  that  of  the  superior  oblique. 

Rectus  Capitis  Posticus  Minor,  also  triangular,  arises  narrow  from  the 
posterior  part  of  the  atlas ; passes  upwards,  outwards  and  backwards,  and  is 
inserted  broad  into  the  occipital  bone,  behind  the  foramen  magnum.  Use,  to 
assist  the  former  in  drawing  back  the  head,  and  steadying  it  on  the  spine  : this 
pair  is  partly  covered  by  the  last  muscles;  a portion  of  them,  however,  is 
seen  between  these:  both  the  recti  resemble  the  continuation  of  the  inter- 
spinous  muscles. 

OBLiquus  Capitis  Inferior,  is  the  strongest  of  these  small  muscles  ; it 
arises  inferior  and  external  to  the  posterior  rectus,  and  superior  to  the  spinalis 
colli,  from  the  spinous  process  of  the  2d  vertebra,  ascends  obliquely  back- 
wards and  outwards,  and  is  inserted  into  the  extremity  of  the  transverse  pro- 
cess of  the  atlas.  Use,  to  rotate  the  head  and  atlas  on  the  2d  vertebra,  co- 
operating with  the  splenius  of  the  same  side  : and  the  sterno-mastoid  of  the 
opposite  side;  this  muscle  is  covered  by  the  complexus,  trachelo-mastoideus, 
and  trapezius. 

Obliquus  Capitis  Superior,  smaller  than  the  last,  above  the  insertion  of 
which  it  arises,  narrow,  from  the  upper  part  of  the  transverse  process  of  the 
atlas,  ascends  obliquely  inwards,  overlapping  the  rectus,  and  is  inserted  broad 
into  the  occipital  bone,  between  its  transverse  ridges,  just  behind  the  mastoid 
process.  Use,  to  bend  the  head  to  one  side,  and  draw  it  a little  backwards  ; 
any  rotatory  power  it  can  exert  (which  must  be  slight)  will  oppose  the  last 
described  muscle.  In  the  dissection  of  the  muscles  of  this  region,  but  few 
vessels  or  nerves  of  size  or  note  are  met  with ; the  arteries  which  supply 
these  muscles  are  branches  of  the  occipital  and  deep  cervical  superiorly  ; 
the  posterior  branches  of  the  intercostal  in  the  middle,  and  of  the  lumbar 
arteries  below ; the  nerves  are  the  small  posterior  branches  of  the  cervical, 
dorsal  and  lumbar  spinal  nerves. 


OR  MANUAL  OF  ANATOMY. 


55 


CHAPTER  Y. 

DISSECTION  OF  THE  UPPER  EXTREMITY. 

The  upper  extremity  is  connected  to  the  trunk  by  the  sterno-clavicular  lig- 
aments, and  by  ten  muscles,  of  which  one  is  connected  to  the  clavicle  (sub- 
clavius),  one  to  the  humerus  (pectoralis  major),  and  eight  to  the  scapula,  viz. 
Trapezius,  levator  anguli  scapulae,  omo-hyoid,  rhomboid  major  and  minor, 
serratus  magnus,  pectoralis  minor,  and  latissimus  dorsi ; this  last  is  also 
inserted  into  the  humerus ; all  these  muscles  have  been  already  examined ; 
these  the  student  may  divide,  then  separate  the  extremity  from  the  trunk, 
and  place  a block  under  the  axilla  ; the  dissection  of  the  arm,  however,  may 
be  performed  while  it  remains  connected  to  the  body.  The  muscles  of  the 
upper  extremitv  are  classed  into  those  of  the  shoulder  and  arm,  forearm  and 
hand. 

§ 1. — Dissection  of  the  Muscles  of  the  Shoulder  and  Arm. 

Dissect  off  the  integuments  from  the  shoulder  and  arm  as  low  as  the  bend 
of  the  elbow;  beneath  the  skin  and  adipose  substance  is  the  brachial  aponeu- 
rosis ; this  is  weak  and  imperfect  in  some  situations,  as  on  the  deltoid  muscle ; 
in  others  it  is  strong  and  well  marked,  and  it  increases  in  strength  as  it  de- 
scends: it  is  connected  posteriorly  to  the  spine  of  the  scapula,  and  to  the 
infra-spinatus  muscle;  inferior  to  this  it  receives  an  addition  of  fibres  from 
the  insertion  of  the  deltiod ; internally  it  is  in  part  continued  along  the  vessels 
from  the  fascia  of  the  axilla,  and  in  part  also  from  the  tendons  of  the  great 
pectoral  and  latissimus  dorsi;  it  invests  the  whole  arm,  confining  the  muscles 
in  their  situation,  and  pressing  them  towards  each  other,  particularly  along 
the  inner  side  of  the  arm,  so  as  to  overlap  the  brachial  vessels  and  nerves  : as 
it  descends  it  adheres  to  the  lateral  ridge  of  the  humerus,  which  lead  to  the 
condyles ; these  connections  are  named  inter-muscular  ligaments  ; the  internal 
is  augmented  by  a prolongation  of  the  coraco-brachialis  tendon,  and  the  ex- 
ternal by  fibres  from  the  deltoid  ; the  fascia  of  the  forearm  we  shall  examine 
afterwards.  Between  the  integuments  and  fascia  of  the  arm  we  notice  two 
cutaneous  veins,  the  cephalic  on  the  outer,  and  the  basilic  on  the  inner  side  : 
the  cephalic  will  be  found  hereafter  to  commence  about  the  thumb,  and  to 
ascend  along  the  radial  side  of  the  forearm,  and  having  passed  the  elbow  joint, 
it  is  now  seen  continuing  its  course  up  the  arm,  at  first  on  the  outside  of  the 
biceps,  and  afterwards  between  the  deltoid  and  great  pectoral  muscles  to  the 
clavicle,  beneath  which  it  sinks  to  join  the  axillary  vein ; the  cephalic  vein  is 
unaccompanied  by  nerves  in  its  course  up  the  arm,  but  in  the  dissection  of  the 
forearm  the  external  cutaneous  nerve  will  be  seen  closely  connected  with  it. 
The  basilic  vein  will  be  found  to  commence  about  the  little  finger,  to  ascend 
along  the  ulnar  side  of  the  forearm,  and  to  pass  over  the  elbow  joint ; it  is 
now  seen  continuing  its  course  on  the  inner  side  of  the  biceps,  between  the 
skin  and  facia,  and  about  the  middle  of  the  arm  it  perforates  the  latter,  to 
join  one  of  the  deep  brachial  veins  ; in  some  it  continues  superficial  as  high 
as  the  axilla,  where  it  joins  the  axillary  vein ; the  basilic  vein  in  the  arm  is 


56 


THE  DUBLIK  DISSECTOR, 


accompanied  by  the  cutaneous  nerves  of  Wrisberg,  which  having  escaped 
from  the  intercostal  branches  of  the  2d  and  3d  dorsal  nerves,  and  passed 
across  the  axilla,  are  then  distributed  to  the  integuments  on  the  inner  side 
of  the  arm ; inferiorly  the  internal  cutaneous  branch  of  the  brachial  plexus 
accompanies  this  vein,  and  continues  with  it  along  the  forearm;  dissect  off 
the  fascia  and  cellular  membrane  from  the  muscles  of  the  shoulder  and  arm. 
The  muscles  of  the  shoulder  are  the  deltoid,  supra  and  infra  spinatus,  teres 
minor  and  major,  and  sub-scapularis  , those  of  the  arm  are  the  biceps,  coraco- 
brachialis,  brachialis  anticus  and  triceps; — first  examine  the  muscles  of  the 
shoulder. 

Deltoides,  very  thick  and  strong,  triangular,  arises  tendinous  from  the 
lower  edge  of  the  spine  of  the  scapula,  and  rather  fleshy  from  the  anterior 
edge  of  the  acromion,  and  of  the  external  third  of  the  clavicle  ; the  fibres  con- 
verge and  descend  obliquely,  the  posterior  forwards,  the  anterior  backwards, 
and  the  middle  at  first  outwards,  and  then  vertically  downwards  ; inserted 
tendinous  into  a rough  surface,  about  two  inches  in  extent,  situated  on  the 
outer  side  of  the  humerus,  and  commencing  just  above  its  centre.  Use,  to 
abduct  and  raise  the  arm,  the  anterior  fibres  can  also  draw'  it  forwards,  the 
posterior  backwards,  and  when  the  arm  is  by  the  side,  these  portions  can  ro- 
tate it  inwards  or  outwards.  This  muscle  can  also  move  the  scapula  on  the 
arm  when  the  latter  is  fixed,  as  in  the  case  of  a fall  upon  the  hand  or  elbow, 
or  in  lifting  a very  heavy  weight ; under  these  circumstances  this  muscle  some- 
times co-operates  with  the  great  pectoral  and  latissimus  dorsi,  to  dislocate  the 
head  of  the  humerus  into  the  axilla.  The  deltoid  is  covered  only  by  the  skin, 
and  a few  fibres  of  the  platisma;  its  origin  corresponds  to  the  insertion  of 
the  trapezius,  with  which  it  is  often  connected  by  aponeurotic  fibres;  its  in- 
sertion is  surrounded  by  the  origin  of  the  brachiseus  anticus,  and  lies  between 
the  biceps  and  second  head  of  the  triceps ; its  posterior  margin  is  thin,  and 
sends  off  an  aponeurosis  to  cover  the  infra-spinatus  muscle;  its  anterior  edge 
is  separated  from  the  great  pectoral,  by  the  cephalic  vein,  some  cellular  mem- 
brane, and  a small  artery.  This  muscle  is  fleshy  on  its  external  surface, 
coarse  and  rough,  and  composed  of  several  distinct  triangular  fasciculi.  Divide 
it  transversely,  and  reflect  each  portion,  and  we  shall  then  see  that  its  struc- 
ture is  very  complex,  and  that  its  internal  surface  is  much  more  tendinous,  a 
large  bursa  also  is  seen  beneath  it;  this  bursa  extends  under  the  acromion, 
and  is  expanded  on  the  tendon  of  the  supra-spinatus,  and  on  the  capsular  li- 
gament; it  allows  the  deltoid  muscle  and  the  exterior  of  the  shoulder  joint 
to  glide  easily  against  each  other ; the  deltoid  also  covers  the  coracoid  process, 
the  muscles  which  are  attached  to  it,  all  the  small  muscles  connected  to  the 
capsular  ligament,  the  insertion  of  the  great  pectoral,  and  the  circumflex  ves- 
sels and  nerves. 

Sijpr\-Spinatus,  fills  the  fossa  of  that  name,  and  arises  from  all  that  por- 
tion of  the  scapula  above  its  spine,  which  is  engaged  in  forming  this  fossa, 
also  from  a strong  fascia  which  covers  the  muscle  ; the  fibres  pass  forwards 
beneath  the  acromion  process  and  triangular  ligament,  end  in  a tendon  which 
glides  over  the  neck  of  the  scapula  (a  bursa  intervenes) ; inserted  into  the 
upper  and  forepart  of  the  great  tuberosity  of  the  humerus,  into  the  most  ante- 
rior of  the  three  depressions  which  are  marked  on  that  surface.  Use,  to 
assist  the  deltoid  in  raising  and  abducting  the  arm,  it  also  strengthens  the 


OR  MANUAL  OF  ANATOMY. 


57 


capsular  ligament,  and  draws  it  out  of  the  angle,  which  is  formed  by  the  elevation 
of  the  arm,  between  the  humerus  and  the  glenoid  cavity;  it  also  presses  the 
head  of  the  humerus  and  glenoid  cavity  towards  each  other,  prevents  the  head 
of  the  former  from  descending  out  of  the  latter,  and  thus  it  becomes  the  an- 
tagonist to  the  pectoral,  deltoid,  and  those  other  long  muscles,  which  have  a 
tendency  to  dislocate  the  head  of  the  bone  into  the  axilla.  This  muscle  is 
covered  by  the  trapezius,  much  cellular  membrane,  and  fat,  and  by  a strong 
aponeurosis;  its  insertion  is  concealed  by  the  deltoid,  and  the  large  bursa 
beneath  that  muscle,  also  by  the  acromion  process  and  triangular  ligament;  tire 
tendon  is  inseparably  connected  to  the  capsular  ligament. 

Infka-Spinatus,  is  inferior  to  the  last,  flat  and  triangular ; arises  fleshy 
from  the  inferior  surface  of  the  spine  of  the  scapula,  and  from  the  dorsum  of 
this  bone,  below  this  process,  as  low  down  as  the  posterior  ridge  on  the  infe- 
rior costa,  also  from  the  aponeurosis  which  covers  it;  the  inferior  fibres  ascend 
obliquely  forwards,  the  superior  run  horizontally ; all  converge,  and  are  in- 
serted by  a strong  tendon,  which  covers  and  adheres  to  the  outer  pa' t of  the 
capsular  ligament,  into  the  middle  of  the  external  tuberosity  of  the  humerus, 
below  the  supra-spinatus.  Use,  to  assist  the  superior  part  of  the  deltoid  in 
raising  the  arm,  and  drawing  it  backwards,  also  in  rotating  it  outwards;  when 
the  arm  has  been  raised,  its  lower  fibres  can  depress  it;  it  will  also  draw  the 
capsular  ligament  out  of  the  joint,  and  strengthen  the  articulation  ; it  is  covered 
by  the  trapezius  and  deltoid ; but  between  these  and  the  latissimus  dorsi,  a 
portion  of  it  is  superficial.  It  lies  on  the  bone,  and  the  scapular  vessels  and 
nerves  ; a large  bursa  lies  between  its  tendon  and  the  neck  of  the  scapula. 

Teres  Minor,  small  and  narrow,  inseparably  attached  to  the  last  muscle, 
along  the  edge  of  which  it  runs;  it  arises  from  a depression  between  the  two 
ridges  on  the  inferior  costa  of  the  scapula,  from  the  fascia  which  covers  it,  and 
from  ligamentous  septa,  which  enclose  it;  the  fibres  ascend  obliquely  forwards 
and  outwards,  cover  and  adhere  to  the  capsule,  and  are  inserted  below  the 
infra-spinatus  into  the  inferior  depression  on  the  great  tuberosity  of  the  hume- 
rus. Use,  to  co-operate  with  the  last  muscle.  The  origin  of  the  teres  minor 
is  between  and  overlapped  by  the  infra-spinatus  and  teres  major  muscles;  its 
middle  portion  is  superficial,  and  its  insertion  is  covered  by  the  deltoid;  it 
lies  on  the  scapula,  subscapular  vessels,  capsular  ligament,  and  long  head  of 
the  triceps,  which  last  separates  it  from  the  teres  major. 

Sub-Scapularis,  is  situated  on  the  inner  side  of  the  scapula,  opposite  to 
the  three  last  described  muscles,  broad  and  triangular,  the  base  behind,  the 
apex  before ; it  arises  from  all  the  surface  and  circumference  of  the  sub-sca- 
pular fossa,  the  fibres  run  in  thick  fasciculi  upwards  and  forwards,  and  all 
converge  towards  the  neck  of  the  capsula,  over  which  they  glide,  beneath  the 
coracoid  process,  and  the  muscles  which  are  inserted  into  it ; they  end  in  a 
tendon  which  is  intimately  united  to  the  scapular  ligament,  and  inserted  into 
the  internal  or  small  tubercle  of  the  humerus  ; this  muscle  is  covered  by  the 
scapula  and  the  muscles  of  the  shoulder ; its  inferior  edge  is  in  contact  with 
the  teres  major ; its  internal  surface,  which  forma  part  of  the  axilla,  is  con- 
nected to  the  serratus  magnus,  and  to  the  axillary  vessels  and  nerves,  by 
loose  cellular  membrane : a large  bursa,  very  often  communicating  with  the 
joint,  lies  between  its  tendon  and  the  neck  of  the  scapula,  beneath  the  coracoid 
process : another  smaller  bursa  is  sometimes  situated  lower  down,  between 
8 


58 


THE  DUBLIN  DISSECTOR, 


the  tendon  and  the  capsular  ligament.  Use,  this,  which  is  the  strongest  of 
these  capsular  muscles,  strengthens  the  inner  side  of  the  articulation,  and 
guards  against  dislocation  when  the  elbow  is  suddenly  drawn  backwards  and 
outwards.  This  muscle  can  abduct  the  arm,  draw  it  backwards,  and  rotate 
it  inwards,  so  as  to  turn  the  palm  of  the  hand  backwards. 

These  four  capsular  muscles,  which  have  been  just  described,  are  of  great 
use  to  the  shoulder  articulation ; the  head  of  the  humerus  is  so  large,  the 
glenoid  cavity  so  superficial,  and  the  capsular  ligament  so  loose  and  long, 
that,  but  for  these  muscles,  the  bones  could  not  remain  in  apposition  ; hence, 
in  cases  of  paralysis  of  the  muscles  of  this  region,  the  joint  becomes  elongated 
and  flattened,  and  a partial  dislocation  exists:  in  the  dissecting  room  also,  if 
we  divide  all  the  muscles  surrounding  the  capsule,  and  leave  the  latter  unin- 
jured, the  bones  will  no  longer  be  in  contact:  these  muscles,  therefore,  serve 
to  strengthen  the  capsule,  to  keep  the  head  of  the  humerus  pressed  against  the 
glenoid  cavity,  and  thus  to  counteract  that  tendency  to  dislocate  the  head  of 
the  bone,  which  the  larger  muscles  of  the  limb  frequently  have,  in  consequence 
of  their  insertion  being  at  such  a distance  from  the  centre  of  the  joint,  added 
to  the  anatomical  imperfections  in  the  latter  already  alluded  to ; which  im- 
perfections, however,  are  much  counter-balanced  by  the  great  mobility  which 
the  joint  enjoys  in  consequence  of  this  formation,  by  the  numerous  opposing 
muscles  which  serve  to  protect  the  articulation,  and  by  the  rotatory  motion 
of  which  the  scapula  is  allowed  to  partake. 

Teres  Major,  long  and  flat,  arise  from  a rough,  flat  surface  on  the  inferior 
angle  of  the  scapula,  below  the  infra-spinatus;  it  forms  a thick  fleshy  belly, 
which  ascends  forwards  and  outwards  to  the  inner  side  of  the  arm,  and  ends 
in  a broad,  thin  tendon,  which  is  at  first  closely  connected  to  the  back  of  the 
tendon  of  the  latissimus  dorsi ; but  near  the  humerus,  a small  bursa  inter- 
venes, and  is  inserted  into  the  inner  or  posterior  edge  of  the  bicipital  groove, 
behind  the  tendon  of  the  latissimus,  and  in  general,  but  not  always,  extend- 
ing lower  down  than  it.  Use,  to  rotate  the  humerus  inwards,  and  to  draw  i: 
downwards  and  backwards ; also  to  draw  forward  the  inferior  angle  of  the 
scapula;  it  thus  assists  the  capsular  muscles  in  retaining  these  two  bones  in 
apposition.  The  origin  of  this  muscle  is  superficial,  the  latissimus  dorsi 
sometimes  overlaps  it;  it  is  here  connected  to  the  infra-spinatus  and  teres 
minor;  from  the  latter  the  long  head  of  the  triceps  afterwards  separates  it; 
it  passes  anterior  to  this  muscle,  and  assists  the  latissimus  in  forming  the  pos- 
terior fold  of  the  axilla.  The  muscles  of  the  arm  are  the  coraco-brachialis, 
biceps,  and  brachiaeus  anticus  anteriorly,  and  the  triceps  posteriorly. 

Coraco-brachialis  arises  tendinous  and  fleshy  from  the  point  of  the  cora- 
coid process,  and  from  the  tendon  of  the  short  head  of  the  biceps ; it  descends 
obliquely  forwards,  and  is  inserted,  chiefly  tendinous,  into  the  internal  side 
of  the  humerus,  about  the  middle,  and  into  the  ridge  leading  to  the  internal 
condyle,  by  an  aponeurosis,  which  forms  the  internal  inter-muscular  ligament, 
which  is  joined  to  the  fascia  of  the  arm.  Use,  to  adduct,  raise,  and  draw  for- 
wards the  arm ; also  to  rotate  it  outwards.  The  origin  of  this  muscle  cannot 
be  separated  from  the  short  head  of  the  biceps,  but  as  it  descends,  it  lies  be- 
hind, and  to  the  inner  side  of  that  muscle  ; it  is  covered  above  by  the  deltoid 
and  pectoral ; a small  portion  of  it  below  is  superficial,  and  is  seen  between 
the  biceps  and  triceps ; its  insertion  is  just  below  that  of  the  teres  major,  and 


OR  MANUAL  OF  ANATOMY. 


59 


separates  the  brachiaeus  anticus  and  posticus : the  coraco-brachialis  passes 
over  the  tendon  of  the  subscapular,  latissimus  and  teres  muscles ; the  brachial 
artery  and  median  nerve,  at  first  lie  to  its  inner  side,  but  pass  superficial  to 
its  insertion ; the  belly  of  this  muscle  is  generally,  but  not  always,  perforated 
by  the  external  cutaneous,  or  perforans  casserii  nerve. 

Biceps,  is  situated  along  the  fore  part  of  the  humerus,  and  consists  of  two 
portions  superiorly,  the  external  or  long,  the  internal  or  short ; the  internal 
arises  tendinous  from  the  coracoid  process,  between  the  coraco-brachialis  and 
triangular  ligament;  it  soon  becomes  fleshy,  descends  obliquely  outwards, 
and  a little  above  the  middle  of  the  humerus  is  united  to  the  external  or  long 
head,  which  arises  by  a long  tendon,  from  the  upper  part  of  the  glenoid  liga- 
ment of  the  scapula ; this  tendon  passes  outwards  to  the  joint  and  over  the 
head  of  the  humerus ; it  then  descends  into  the  groove,  between  the  two 
tuberosities  of  this  bone,  in  which  groove  it  is  bound  down  by  tendinous  fibres, 
continued  from  the  capsular  ligament,  and  from  the  adjacent  tendons;  the 
synovial  membrane  of  the  joint  is  reflected  on  this  tendon  at  its  origin,  and  is 
again  reflected  from  it  interiorly  on  the  parietes  of  the  groove,  between  the 
tendons  of  the  great  pectoral,  latissimus  dorsi  and  teres  major  muscles ; thus, 
although  the  tendon  passes  through  the  cavity  of  the  joint,  it  is,  strictly  speak- 
ing, external  to  the  synovial  membrane.  A little  below  the  middle  of  the 
humerus,  these  two  portions  of  the  biceps  unite  in  a large  fleshy  belly,  which 
descending  to  within  about  an  inch  and  a half  of  the  elbow  joint,  ends  in  a 
flat  tendon ; this  sends  off  a process  called  the  semilunar  fascia,  to  join  the 
general  aponeurosis  of  the  forearm,  and  then  sinks  below  the  joint  into  a tri- 
angular hollow  between  the  supinator  longus  and  pronator  teres,  and  is  in- 
serted into  the  back  part  of  the  tubercle  of  the  radius : a bursa  intervenes 
between  this  tendon  and  the  anterior  part  of  the  tubercle,  which  is  covered 
by  cartilage;  the  semilunar  fascia,  which  arises  narrow  from  the  fore  part  of 
this  tendon,  opposite  the  bend  of  the  elbow,  passes  upward  and  inwards,  ex- 
panding towards  the  internal  condyle,  to  which,  and  to  the  muscles  proceeding 
from  it,  some  of  its  fibres  are  attached ; the  remaining  become  continuous 
with  the  aponeurosis  of  the  forearm.  Use,  to  flex  the  forearm,  and  make  tense 
its  fascia;  also,  to  abduct  and  raise  the  arm.  When  the  hand  is  prone,  the 
first  effect  of  the  contraction  of  the  biceps  is  to  roll  the  radius  outwards,  and 
turn  the  hand  supine;  the  long  tendon  of  the  biceps,  by  passing  over  the  head 
of  the  humerus,  prevents  this  bone  being  dislocated  upwards  and  outwards, 
as  otherwise  might  occur,  in  consequence  of  a fall,  or  of  a sudden  muscular 
contraction : the  biceps  may  also  assist  the  coraco-brachialis,  in  rotating  the 
scapula  on  the  humerus,  so  as  to  depress  the  point  of  the  shoulder.  The  long 
head  of  the  biceps  is  concealed  by  the  deltoid,  supra-spinatus  and  capsular 
ligament;  the  short  head,  by  the  great  pectoral  and  deltoid:  notunfrequently 
this  muscle  has  another  origin  from  the  humerus  below  its  head;  in  some  a 
fasciculus  unites  it  to  the  coraco-brachialis,  and  in  others  to  the  brachiaeus 
anticus  muscle,  which  lies  behind  it.  The  belly  of  the  biceps  is  superficial, 
and  lies  on  the  brachialis  anticus : the  brachial  artery  descends  along  its 
internal  border,  and  somewhat  overlapped  by  it,  in  the  middle  and  lower  part 
of  the  arm.  This  muscle  or  its  tendon  will  serve  as  a guide  in  the  living  sub- 
ject, in  case  we  are  required  to  tie  this  vessel,  but  superiorly  the  coraco-bra- 
chialis intervenes:  the  semilunar  fascia  is  extended  over  the  trunk  of  this 


60 


THE  DUBLIN  DISSECTOR, 


artery  and  nerve,  and  affords  them  some,  but  not  a constant  protection,  in  the 
operation  of  venaesection  in  the  median  basilic  vein,  which  vein  is  superficial 
to  this  fascia,  but  parallel,  and  often  so  close  to  the,  artery  as  to  expose  the 
latter  to  some  degree  of  danger  in  that  operation. 

Brachialis  Anticus,  or  Externus,  improperly  called  by  some  Internes, 
arises  from  the  centre  of  the  humerus  by  two  fleshy  slips,  one  on  either  side 
of  the  insertion  of  the  deltoid,  from  the  fore  part  of  the  bone  down  to  the 
condyles,  and  on  each  side  as  far  as  the  intermuscular  ligaments ; the  fibres 
descend  converging,  pass  anterior  to  the  elbow  joint,  adhere  to  the  synovial 
membrane,  and  are  inserted  by  a strong  tendon  into  the  coronoid  process  of 
the  ulna,  and  into  a rough  surface  on  this  bone  beneath  that  process.  Use , to 
flex  the  forearm,  and  in  doing  so  it  draws  the  synovial  membrane  out  of  the 
angle  of  the  joint;  it  also  strengthens  this  articulation  in  its  extended  state, 
by  pressing  the  ulna  against  the  humerus,  and  supporting  the  joint  in  front: 
this  muscle  is  covered  by  the  biceps  and  by  the  brachial  vessels  and  nerves  ; 
external  to  the  biceps  it  is  superficial ; its  external  head  is  the  longer,  and  lies 
between  the  deltoid  and  second  head  of  the  triceps;  the  internal  separates 
the  deltoid  from  the  coraco-brachialis ; the  tendon  passes  deep  into  the  hollow 
at  the  elbow,  behind  the  tendon  of  the  biceps,  and  is  inserted  on  its  internal 
side:  a fleshy  fasciculus  often  unites  this  muscle  and  the  biceps  about  the 
middle  of  the  arm. 

Triceps  Extensor  Cubiti,  covers  the  back  part  of  the  humerus,  and  ex- 
tends from  the  scapula  to  the  olecranon  ; it  consists  superiorly  of  three  por- 
tions, viz.  the  middle  or  long  head,  the  second  or  external  head,  and  the  third 
or  internal,  or  short  head,  or  brachiseus  internus  or  posticus. 

The  long,  or  middle  head,  arises  by  a flat  short  tendon  about  an  inch  broad, 
from  the  lower  part  of  the  neck  of  the  scapula,  and  from  the  anterior  portion 
of  the  inferior  costa;  it  also  adheres  to  the  inferior  part  of  the  capsular  liga- 
ment; it  soon  ends  in  a large  fleshy  belly  which  decends  along  the  back  part 
of  the  humerus,  that  surface  which  is  towards  the  bone  continues  tendinous 
for  some  distance;  about  the  superior  third  of  the  arm  it  joins  the  second  or 
external  head,  which  arises  immediately  below  the  insertion  of  the  teres  mi- 
nor, by  a narrow  tendinous  and  fleshy  slip,  from  a ridge  on  the  outer  side  of 
the  humerus  commencing  below  the  great  tuberosity,  and  leading  down  to 
the  external  condyle;  it  also  arises  from  the  bone  behind  this  ridge,  from  the 
intermuscular  ligament,  and  from  the  external  condyle,  by  a tendon  which 
passes  upwards  and  inwards,  and  joins  the  remainder  of  the  muscle ; these 
inferior  fibres  are  parallel  to  the  anconaeus;  the  third,  or  short  head,  or  bra- 
chiaeus  internus,  or  posticus,  improperly  called  brachiaeus  externus,  arises 
narrow  on  the  inside  of  the  humerus,  above  its  centre,  commencing  tendinous 
just  below  the  insertion  of  the  teres  major,  and  continuing  to  arise  from  the 
ridge  which  leads  to  the  internal  condyle,  and  from  the  internal  intermuscular 
ligament;  these  three  portions  of  the  triceps  unite  above  the  middle  of  the 
arm,  and  descending  along  its  posterior  part,  end  in  a flat  broad  tendon  which 
consists  of  two  laminae,  a superficial  and  a deep  ; the  former  is  continued  into 
the  fascia  on  the  back  part  of  the  forearm,  the  latter,  which  is  stronger  but  nar- 
rower, is  inserted  into  the  olecranon  process.  Use,  to  extend  the  forearm  on  the 
arm  and  by  its  long  portion  to  carry  the  arm  backwards,  and  in  some  cases  to 
abduct  it;  it  also  draws  up  the  synovial  membrane  from  between  the  olecranon 


OR  MANUAL  OF  ANATOMY. 


61 


process  and  the  humerus,  and  thus  protects  it  from  pressure  in  the  extended 
state  of  the  limb.  The  long  head  gives  support  to  the  inferior  part  of  the 
capsula  ligament  of  the  shoulder,  and  so  tends  to  protect  that  joint  against 
dislocation,  in  that  situation  where  it  would  be  most  likely  to  occur.  The 
sudden  contraction  of  the  triceps  during  life  sometimes  breaks  off  the  olecra- 
non process,  and  draws  upwards  the  separated  portion,  of  course  the  indivi- 
dual loses  for  some  time  the  power  of  extending  the  forearm ; the  fractured  piece, 
however,  is  prevented  being  separated  to  any  considerable  distance  by  the  apo- 
neurosis of  the  triceps  which  covers  the  olecranon  and  which  joins  the  fascia  of 
the  forearm,  and  also  by  the  inferior  fibres  of  this  muscle,  which  being  connected 
to  the  condyles,  and  having  to  ascend  a little  to  the  olecranon,  tend  to  draw 
down  its  fractured  portion.  The  1st,  or  long  head  of  the  triceps,  arises 
betweeen  the  two  teres  muscles  ; the  second,  or  outer  head,  below'  the  teres 
jninor;  and  the  third,  or  the  brachiaeus  internus,  or  posticus,  below  the  teres 
major ; the  long  and  the  second  heads  are  covered  above  by  the  deltoid,  the 
remainder  of  them  is  superficial;  the  second  lies  external  to  the  supinator 
longus  and  radial  extensors  of  the  carpus;  the  third  or  internal  head  is  also 
superficial,  and  lies  between  the  brachialis  antitieus  and  coraco-brachialis 
anteriorily,  and  the  long  portion  of  the  triceps  posteriorly;  the  ulnar  nerve 
descends  along  this,  and  the  radial  or  spiral,  separates  it  from  the  second  or 
outer  head  ; a small  bursa  lies  between  the  tendon  and  the  point  of  the  ole- 
cranon, a larger  one  between  the  skin  and  the  aponeurosis  which  covers  that 
process ; this  superficial  bursa  is  peculiarly  liable  to  inflammation,  which  is 
generally  of  an  unhealthy  character,  in  consequence,  of  an  injury,  such  as  a 
fall  upon  the  elbow  producing  a superficial  lacerated  wound.  In  the  dissec- 
tion of  the  muscles  of  the  arm,  w'e  should  notice  the  course  of  the  brachial 
artery  and  of  its  principal  branches,  also  the  divisions  of  the  axillary  plexus  of 
nerves : the  cutaneous  veins  have  been  already  noticed ; the  deep  veins 
accompany  the  arteries,  two  to  each. 

The  brachial  artery  which  is  the  continuation  of  the  subclavian  and  axil- 
lary, descends  obliquely  outwards  along  the  inner  side,  first  of  the  coraco- 
brachialis,  and  afterward  of  the  biceps  ; near  the  elbow  it  inclines  forwards, 
and  then  sinks  beneath  the  fascia  of  the  biceps,  and  a little  below  the  bend 
of  the  elbow  it  divides  into  the  radial  and  ulnar  arteries.  In  this  course  it  is 
covered  by  the  fascia  and  integuments,  and  overlapped  a little  by  the  biceps; 
it  is  surrounded  by  a sheath  of  cellular  membrane,  which  also  contains  the 
two  vense  comites;  the  internal  cutaneous  nerve  lies  superficial  to  it ; the 
median  or  brachial  is  also  superficial  to  it  above,  and  rather  to  its  outer  side, 
about  the  middle  of  the  arm,  it  crosses  the  artery,  and  inferiorly  it  is  almost 
always  to  its  ulnar  or  inner  side.  The  ulnar  nerve  lies  internal  to  the  artery, 
and  at  some  distance  from  it  inferiorly ; the  radial  or  spiral  nerve  is  posterior 
to  it,  and  separates  it  above  from  the  triceps.  In  this  course  the  artery 
passes  over  the  tendons  of  the  latissimus  and  teres,  a small  part  of  the  tri- 
ceps, the  coraco-brachialis,  and  the  brachiaeus  anticus.  The  brachial  artery 
gives  off  several  muscular  branches  from  its  external  side;  and  from  its 
internal,  the  superior  profunda,  which  accompanies  the  spiral  nerve  round  the 
back  of  the  humerus  to  its  external  side;  the  inferior  profunda  which 
descends  along  with  the  ulnar  nerve  towards  the  inner  condyle,  and  the 


62 


THE  DUBLIN  DISSECTOR, 


anastomotica  magna,  which  runs  towards  the  inner  side  of  the  elbow  joint.— 
See  Anatomy  of  the  Vascular  System. 

The  branches  of  the  brachial  plexus  of  nerves,  which  are  met  with  in  the 
dissection  of  the  arm,  are  six  in  number:  1st  the  internal  cutaneous,  which 
has  been  already  noticed;  2d,  the  external  cutaneous,  or  musculo  cutaneous, 
or  perforans  casserii,  pierces  the  coraco-brachialis  muscle,  descends  obliquely 
outwards  between  the  biceps  and  brachialis  anticus,  to  which  it  sends  several 
filaments,  and  at  the  anterior  edge  of  the  supinator  longus  it  becomes  cuta- 
neous, descending  along  with  the  cephalic  vein  and  its  branches ; 3d,  the 
median  or  brachial  nerve  accompanies  the  brachial  artery  to  the  bend  of  the 
elbow,  and  sinks  beneath  the  muscles  of  the  forearm,  in  the  dissection  of 
which  the  remainder  of  its  course  will  be  exposed ; 4th,  the  ulnar  nerve 
descends  along  the  inner  portion  of  the  triceps,  or  the  braclviaeus  internus, 
runs  behind  the  inner  condyle,  and  is  then  distributed  to  the  muscles  of  the 
forearm  and  hand  ; 5th,  the  musculo-spiral,  or  radial  nerve,  descends  between 
the  second  and  third  heads  of  the  triceps,  and  winds  round  the  back  part  of 
the  humerus,  supplying  the  triceps  in  its  course ; it  next  runs  spirally  forwards 
to  the  forepart  of  the  bone,  between  the  supinator  longus  anil  brachialis  anti- 
cus ; it  then  descends  over  the  forepart  of  the  elbow  joint  to  the  muscles  of 
the  forearm,  where  we  shall  trace  it  afterwards  ; 6th,  the  circumflex,  or  arti- 
cular nerve,  accompanied  by  the  posterior  circumflex  artery,  passes  out  of 
the  axilla  between  the  long  head  of  the  triceps  and  the  neck  of  the  humerus, 
winds  round  the  latter  beneath  the  deltoid  muscle,  to  which  its  branches  are 
distributed. — See  Anatomy  of  Nervous  System. 

§ 2. — j Dissection  of  the  Forearm  and  Hand. 

Remove  the  integuments  from  the  front  and  back  of  the  forearm  and  hand, 
and  the  investing  fascia  will  be  exposed,  together  with  the  cutaneous  nerves 
and  veins : the  latter  may  be  noticed  first.  The  basilic  vein  is  seen  to  arise 
by  small  branches  from  the  sides  of  the  little  finger,  one  of  which  is  named 
salvatella;  it  then  ascends  along  the  ulnar  side  of  the  forearm,  receiving  in 
this  course  small  branches  from  the  front  and  back  of  the  arm,  and  passing 
anterior  to  the  internal  condyle,  it  is  joined  by  the  median  basilic ; it  then 
ascends  along  the  inner  side  of  the  arm,  passes  beneath  the  fascia,  and  joins 
one  of  the  deep  brachial  veins  ; sometimes  it  continues  in  a superficial  course 
to  the  axilla,  and  joins  the  axillary  vein.  The  cephalic  vein  commences  by 
several  small  branches  about  the  thumb  and  back  of  the  hand ; it  ascends 
along  the  radial  side  of  the  forearm,  passes  over  the  bend  of  the  elbow  is 
joined  by  the  median  cephalic,  and  then  ascends  along  the  outside  of  the  arm 
to  the  clavicle.  The  median  vein  arises  by  small  branches  from  the  forepart 
of  the  wrist,  it  ascends  along  the  forearm  between  the  cephalic  and  basilic 
veins,  and  near  the  elbow  divides  into  two  or  three  branches  : 1st,  the  median 
basilic,  which  ascends  obliquely  over  the  fascia  of  the  biceps  to  join  the 
basilic ; 2d,  the  median  cephalic,  which  passes  obliquely  upwards  and  out- 
wards, and  joins  the  cephalic  vein ; the  third  branch  of  the  median,  w hen 
present,  sinks  deep,  and  joins  one  of  the  deep  veins.  The  internal  cuta- 
neous nerve  and  its  branches  accompany  the  basilic  vein,  some  passing 


OR  MANUAL  OF  ANATOMY. 


63 


anterior,  others  posterior  to  it ; the  external  cutaneous,  or  musculo-cutaneous, 
in  general  lies  behind  the  cephalic  vein  at  the  bend  of  the  elbow,  its  branches 
afterwards  twine  around  that  vessel.  The  relation  between  the  cutaneous 
nerves  and  veins  is  liable  to  great  variety. 

The  fascia  of  the  forearm  is  very  strong,  particularly  on  the  posterior  part ; 
it  consists  of  tendinous  fibres,  which  run  in  every  direction,  connected  on 
either  side  to  the  condyles,  and  to  the  muscles  which  are  attached  to  these ; 
it  receives  an  addition  from  the  biceps  before,  and  from  the  triceps  behind  ; 
as  it  descends,  it  invests  the  limb  so  closely  as  to  give  it  a certain  form  ; it 
sends  septa  between  the  different  muscles,  which  give  attachment  to  several 
fibres,  and  it  adheres  very  closely  to  the  ulna  its  whole  length ; interiorly  it 
is  connected-'  to  the  annular  ligaments  of  the  carpus.  The  annular  ligaments 
of  the  wrist  appear  formed  in  part  by  this  fascia,  strengthened  by  proper 
transverse  fibres ; the  posterior  is  attached  to  the  styloid  process  of  the  ulna 
internally,  and  to  that  of  the  radius  externally ; it  binds  down  the  extensor 
tendons.  The  anterior  annular  ligament  is- much  stronger;  it  is  attached  to 
the  unciform  and  pisiform  bones  internally,  to  the  scaphoid  and  trapezium  ex- 
ternally ; its  upper  edge  is  connected  to  the  fascia  of  the  forearm,  its  lower  to 
that  of  the  hand  r this  ligament,  together  with  the  carpus,  forms  a canal  or  ring 
for  the  passage  of  the  flexor  tendons.  The  integuments  of  the  hand  are  thin 
posteriorly,  and  cover  several  cutaneous  veins ; anteriorly  they  are  dense, 
and  the  subjacent  cellular  tissue  granulated  and  firm ; on  the  back  of  the 
hand  a very  thin  aponeurosis  exists,  but  anteriorly,  there  is  a remarkable 
strong  fascia,  the  palmar  fascia : this  is  of  a triangular  form,  commences 
narrow  at  the  annular  ligament,  from  which,  and  from  the  tendon  of  the  pal- 
maris  longus,  it  arises:  it  then  expands  over  the  palm  of  the  hand,  and  near 
the  fingers  divides  into  four  fasciculi,  each  of  which  is  forked  and  inserted 
into  either  side  of  each  of  the  sheaths  of  the  flexor  tendons,  and  into  the  cap- 
sular ligaments  of  the  first  phalanges;  transverse  bands  pass  across  these  di- 
verging fasciculi,  and  several  fibres  penetrate  between  the  tendons,  and  join 
the  metacarpal  bones  and  interosseous  muscles;  a thin  aponeurosis,  derived 
from  the  outer  edge  of  the  palmar  fascia,  covers  the  muscles  of  the  thumb, 
and  a similar  one,  those  of  the  little  finger.  Attached  to  the  palmar  fascia  is 
the  following  small  cutaneous  muscle : 

Palmaris  Brevis,  arises  from  the  annular  ligament  and  palmar  fascia  ; the 
fibres  pass  transversely  inwards,  and  are  inserted  into  the  integuments  on  the 
inner  side  of  the  palm  of  the  hand.  Use,  to  deepen  the  hollow  of  the  palm 
of  the  hand  by  drawing  the  integuments  towards  the  thumb.  We  may  now 
dissect  oft"  the  fascia  of  the  hand  and  forearm,  to  expose  the  muscles ; in  some 
situations  it  is  difficult  and  unnecessary  to  separate  this  from  the  muscular 
fibres  ; beneath  the  palmar  fascia  we  expose  the  superficial  palmar  arch  of 
vessels  and  nerves  passing  across  the  flexor  tendons  and  the  lumbricales 
muscles. 

- The  muscles  of  the  forearm  are  so  very  numerous,  that  it  will  be  found 
convenient  to  class  them  according  to  their  situation  and  their  use.  One  set 
of  these  muscles  is  employed  in  bending  the  forearm,  wrist,  and  fingers ; these 
are  the  flexors  : a second,  nearly  allied  to  these,  have  the  power  of  pronating 
the  hand,  that  is,  of  rolling  the  radius  across  the  ulna,  so  as  to  make  the  palm 
of  the  hand  look  downwards;  these  are  the  pronators:  a third  set,  the 


64 


THE  DUBLIN  DISSECTOR, 


extensors,  can  extend  the  forearm,  hand,  and  fingers  ; and  a four+h,  allied  to 
these,  the  supinators,  can  turn  the  hand  supine;  that  is,  place  the  radius  and 
ulna  on  the  same  plane,  and  make  the  palm  of  the  hand  look  upwards.  The 
pronators  and  flexors  arise  chiefly  from  the  internal  condyle,  and  from 
the  inner  or  ulnar  side  of  the  forearm  ; each  of  these  two  great  divisions  may 
be  arranged  into  a superficial  and  deep  layer. 

The  pronators  and  flexors  arising  from  the  inner  side  of  the  forearm,  are 
eight  in  number : five  in  the  superficial  layer,  three  in  the  deep ; the  five  super- 
ficial are,  the  pronator  teres,  flexor  carpi  radialis,  palmaris  longus,  flexor 
digitorum  sublimus,  and  flexor  carpi  ulnaris  : the  three  deep  muscles  are  the 
flexor  digitorum  profundus,  flexor  pollicis  longus,  and  pronator  quadratus.  In 
the  following  description  of  these  muscles,  the  hand  is  supposed  to  be  turned 
forwards,  the  radius  externally,  and  the  ulna  internally.  The  muscles,  which 
arise  from  the  internal  condyle  of  the  humerus,  are  covered  by  the  fascia  of 
the  biceps ; they  cannot  be  separated  from  each  other  above,  but  have  a com- 
mon origin  from  the  condyle,  the  fascia  and  its  septa,  also  from  the  ulna. 

Pronator  Radii  Teres,  arises  tendinous  and  fleshy  from  the  anterior  part 
of  the  internal  condyle,  from  the  fascia  of  the  forearm  and  its  intermuscular 
septa ; also  by  a small  tendon  from  the  coronoid  process  cf  the  ulna ; the  median 
nerve  separates  these  origins;  the  fibres  pass  obliquely  outwards  over  the 
radius,  and  are  inserted,  chiefly  tendinous,  into  the  outer  and  back  part  of  the 
radius,  about  its  centre.  Use,  to  pronate  the  hand,  by  rolling  the  radius  for- 
wards and  inwards  over  the  ulna;  it  is  also  a flexor  of  the  forearm;  this  is 
the  most  external  of  the  muscles,  arising  from  the  inner  condyle : it  is  super- 
ficial, except  at  its  insertion,  which  is  covered  by  the  supinator  longus,  and  bv 
the  radial  vessels,  and  lies  inferior  to  the  supinator  brevis  : it  forms  the 
internal  boundary  of  the  triangular  hollow  at  the  bend  of  the  elbow,  which 
contains  the  tendon  of  the  biceps,  the  brachial  nerve  and  vessels. 

Flexor  Carpi  Radialis,  arises  narrow  and  tendinous  from  the  inner  con- 
dyle, and  fleshy  from  the  intermuscular  septa ; it  forms  a thick  belly,  which 
lies  very  superficial,  and  ends  in  a prominent  flat  tendon  ; this  descends 
obliquely  outwards,  passes  beneath  the  annular  ligament,  and  is  inserted 
into  the  base  of  the  metacarpal  bone  of  the  index  finger.  Use,  to  bend  the 
hand,  and  assist  in  pronating  it ; this  muscle  is  overlapped  above  by  the  pro- 
nator teres,  and  covered  below  by  the  annular  ligament ; it  arises  and  descends 
at  first  between  the  pronator  teres  and  palmaris  longus,  afterwards  between 
this  latter  and  the  supinator  longus,  from  which  it  is  separated  by  the  radial 
nerve  and  vessels;  the  radial  edge  of  this  tendon  may  serve  as  a guide,  in 
cutting  down  on  the  radial  artery  in  the  living  subject. 

Palmaris  Longus  arises  by  a slender  tendon  from  the  inner  condyle,  and 
from  the  fascia  of  the  forearm  ; forms  a short  belly,  which  ends  in  a flat  ten- 
don ; inserted  near  the  root  of  the  thumb  into  the  annular  ligament  and  palmar 
aponeurosis.  Use , to  bend  the  hand  and  make  tense  the  palmar  fascia;  it 
descends  between  the  flexor  carpi  radialis  and  ulnans,  and  lies  on  the  flexor 
sublimis : it  is  sometimes  wanting. 

Flexor  Carpi  Ulnaris,  arises  tendinous  from  the  internal  condyle,  tendi- 
nous and  fleshy  from  the  inner  side  of  the  olecranon  process ; the  ulnar  nerve 
separates  these  origins ; it  also  arises  by  a tendinous  expansion  from  tne  inner 
edge  of  the  ulna  nearly  its  whole  length,  and  from  the  fascia  of  the  forearm, 


OR  MANUAL  OF  ANATOMY. 


65 


the  fibres  pass  obliquely  forwards  to  a tendon  which  descends  in  front  of  the 
ulna,  and  which  overlaps  the  ulnar  nerve  and  vessels,  and  is  inserted  into  the 
pisiform  bone,  and  by  a few  ligamentous  fibres  into  the  base  of  the  fifth  meta- 
carpal bone;  this  insertion  is  also  connected  to  the  muscles  of  the  little  finger. 
Use,  to  flex  the  hand,  and  adduct  it,  particularly  when  assisted  by  the  extenso- 
carpi  ulnaris  : adduction  of  the  hand,  is  not  so  limited  as  abduction,  in  conse- 
quence of  the  ulna  being  shorter  below  than  the  radius.  This  muscle  is  super- 
ficial, and  lies  internal  and  rather  posterior  to  the  preceding  muscles  ; it  de- 
scends between  the  flexor  sublimis  and  extensor  carpi  ulnaris,  and  lies  upon 
the  flexor  profundus  ; the  tendon  passes  over  the  annular  ligament,  and  is 
connected  to  it  by  a tendinous  slip,  which  also  passes  over  the  ulnar  artery 
and  nerve. 

Flexor  Digitorum  Sublimis  Perforatus,  arises  tendinous  and  fleshy  from 
the  internal  condyle  and  internal  lateral  ligament;  tendinous  from  the  coro- 
noid  process,  and  fleshy  from  the  radius  below  its  tubercle,  internal  to  the 
pronator  teres,  and  between  the  supinator  brevis  and  flexor  pollicis  longus  ; it 
forms  a large  muscle,  which  ends  in  four  tendons ; these  descend,  two  an- 
terior, for  the  middle  and  ring  finger  ; and  two  posterior,  for  the  index  and 
little  finger ; they  all  pass  beneath  the  annular  ligament,  and  proceed  along 
the  palm  of  the  hand,  superficial  to  the  deep  flexor  tendons,  and  beneath  the 
palmar  fascia ; and  at  the  first  phalanx  of  each  finger,  or  opposite  the  head  of 
each  metcarpal  bone,  each  of  these  tendons  becomes  enclosed  in  a strong  sheath, 
with  one  of  the  deep  flexors  ; this  sheath  is  continued  to  the  anterior  extremity 
of  the  second  phalanx.  Near  the  end  of  the  first  phalanx,  each  of  the  super- 
ficial flexor  tendons  is  split  for  the  passage  of  the  tendon  of  the  deep  flexor, 
which  is  continued  on  to  the  last  or  ungual  phalanx;  while  the  divisions  of 
each  of  the  superficial  tendons  become  everted  or  folded  out,  beneath  the 
deep  flexor,  so  as  to  lie  nearer  to  the  bone,  and  are  inserted  into  the  anterior 
part  of  the  second  phalanx.  Use,  to  flex  the  second  joint  of  each  finger  on 
the  hand,  the  hand  on  the  forearm,  and  the  latter  on  the  arm.  The  origin  of 
this  muscle  is  partly  concealed  by  the  three  first  described  muscles,  which 
arise  from  the  internal  condyle,  and  to  which  it  is  connected  by  the  intermus- 
cular septa;  inferiorly  a portion  of  it  is  superficial  between  the  flexor  carpi 
ulnaris  and  palmaris  longus.  The  tendons  of  this  muscle  are  enveloped  in  a 
large  bursa  behind  the  annular  ligament;  this  carpal  bursa  is  connected  an- 
teriorly to  the  annular  ligament,  posteriorly  to  the  carpus,  is  expanded  around 
the  superficial  and  deep  flexor  tendons,  the  median  nerve,  and  the  tendon  of 
the  flexor  pollicis  longus,  and  ends  above  and  below  in  a cul  de  sac,  each  end 
of  which  extends  beyond  the  edges  of  the  annular  ligament.  In  the  palm  of 
the  hand  the  tendons  of  the  flexor  sublimis  are  covered  by  the  integuments, 
palmar  fascia,  and  the  superficial  palmar  arch  of  vessels  and  nerves;  along 
the  fingers  each  tendon  is  enclosed  in  a strong  fibrous  sheath,  which  is  con  - 
tinued to  the  end  of  the  second  phalanx  of  each  finger;  this  sheath,  together 
with  the  anterior  surface  of  the  phalanges,  forms  a complete  canal,  or  tube, 
which,  half  fibrous  and  half  osseous,  is  lined  by  a synovial  membrane,  which 
forms  a cul  de  sac  at  either  extremity ; being  reflected  over  the  tendons  it  en- 
closes, and  forming  several  folds  of  frasna  to  connect  these  tendons  to  this 
canal : this  sheath  is  weak,  opposite  each  articulation,  but  is  very  strong  on 
the  phalanges;  its  anterior  extremity  is  continuous  with  the  insertion  of  the 
9 


66 


THE  DUBLIN  DISSECTOR, 


deep  flexor  tendon.  Divide  the  flexor  sublimis  and  carpi  radialis,  and  the  three 
deep  muscles  will  be  partially  exposed, — namely,  the  flexor  digitorum  pro- 
fundus, flexor  pollicis  longus,  and  nearly  concealed  by  these,  the  pronator 
quadratus. 

Flexor  Digitorum  Profundus  Perforans,  arises  fleshy  from  three  supe- 
rior fourths  of  the  anterior  surface  of  the  ulna,  and  from  the  internal  half  of 
the  interosseous  ligament;  it  sometimes  receives  a small  slip  from  the  radius 
below  its  tubercle ; it  forms  a thick  muscle  which  descends  along  the  middle 
and  ulnar  side  of  the  forearm,  and  ends  in  four  flat  tendons;  these  pass  be- 
neath the  annular  ligament,  enter  the  ligamentous  sheaths  on  the  fingers,  pass 
through  the  slits  in  the  superficial  flexor  tendons,  and  are  inserted  into  the 
last  phalanx  of  each  finger.  Use,  to  bend  the  last  phalanx,  and  to  co-operate 
with  the  superficial  flexor  muscle ; this  muscle  is  covered  by  thoseof  the  super- 
ficial layer,  which  have  been  described ; the  ulnar  vessels,  the  median  and 
ulnar  nerves  also  descend  along  it;  and  it  covers  the  ulna,  the  interosseous 
ligament  and  vessels,  the  pronator  quadratus  and  the  carpus,  and  on  each 
finger  its  tendon  is  superficial  to  that  of  the  flexor  sublimis. 

Flexor  Pollicis  Longus,  arises  from  the  fore  part  of  the  radius,  commencing 
narrow  just  below  its  tubercle,  and  ending  within  about  two  inches  of  the  car- 
pus, and  also  very  frequently  by  a long  and  narrow  tendinous  and  fleshy  slip 
from  the  coronoid  process  ; this  at  first  looks  like  a distinct  muscle  ; all  the 
fibres  descend  obliquely  forwards  to  a tendon,  which  passes  beneath  the  an- 
nular ligament,  then  runs  outwards  between  the  two  portions  of  the  short 
flexor,  and  the  two  sesamoid  tubercles  at  the  extremity  of  the  metacarpal  bone ; 
it  then  enters  a strong  ligamentous  sheath,  and  is  bound  down  by  it  as  far  as 
the  last  phalanx  of  the  thumb,  into  the  middle  of  which  it  is  inserted.  Use, 
to  flex  and  adduct  the  different  joints  of  the  thumb  upon  the  hand,  and  the 
latter  upon  the  forearm.  This  muscle  is  covered  by  the  flexor  sublimis  and 
radialis,  and  by  the  radial  vessels,  and  interiorly  by  the  annular  ligament,  it 
descends  along  the  radial  side  of  the  flexor  profundus. 

Pronator  Quadratus,  is  exposed  by  separating  the  flexor  pollicis  and  pro- 
fundus; it  is  situated  just  above  the  carpus,  and  arises  tendinous  and  fleshy 
from  the  inferior  fifth  of  the  anterior  surface  of  the  ulna;  the  fibres  pass  trans- 
versely outwards,  descend  a little,  and  are  inserted  into  the  anterior  part  of 
the  inferior  fourth  of  the  radius.  Use,  to  roll  the  radius  over  the  ulna,  and 
so  to  pronate  the  hand:  this  muscle  is  covered  by  the  tendons  of  the  preced- 
ing, and  by  the  ulnar  and  radial  vessels,  and  it  lies  on  the  interosseous  liga- 
ment, the  radius  and  the  ulna. 

The  muscles  which  are  situated  on  the  outer  and  back  part  of  the  forearm 
are  supinators  and  extensors,  and  are  also  arranged  into  two  layers,  a super- 
ficial and  deep ; the  superficial  consists  of  seven,  namely,  supinator  radii 
longus,  extensor  carpi  radialis  longus,  and  brevis,  extensor  digitorum  com- 
munis, extensor  minimi  digiti,  extensor  carpi  ulnaris  and  anconseus ; these 
muscles  arise  more  distinctly  than  those  on  the  internal  side  of  the  arm: 
some  of  them,  however,  particularly  those  on  the  back  part,  are  closely  con- 
nected to  each  other,  arising  in  common  from  the  external  condyle  of  the 
humerus,  from  the  posterior  surface  of  the  radius  and  ulna,  the  intermuscular 
ligaments  and  the  fascia,  which  is  partly  derived  from  the  tendon  of  the  triceps. 

Supinator  Radii  Longus,  forms  the  prominence  along  the  outer  and 


OR  MANUAL  OF  ANATOMY. 


6 7 


anterior  part  of  the  forearm,  arises  tendinous  and  fleshy  from  the  external  ridge 
of  the  humerus,  commencing  a little  below  the  deltoid,  and  continuing  to 
within  about  two  inches  of  the  outer  condyle ; it  also  arises  from  the  inter- 
muscular ligament,  which  separates  it  from  the  second  or  outer  head  of  the 
triceps,  between  which  and  the  brachiaeus  anticus  this  muscle  is  situated. 
The  supinator  longus  descends  along  the  outer  and  anterior  part  of  the  elbow, 
and  about  the  middle  of  the  forearm  ends  in  a flat  tendon,  which  descends 
along  the  radius,  and  is  inserted  into  a rough  surface  on  the  outside  of  that 
bone,  near  its  styloid  process.  Use,  to  roll  the  radius  backwards,  so  as  to 
make  the  hand  look  supine;  it  can  also  bend  the  elbow  joint.  This  muscle  is 
superficial ; it  passes  over  the  extensor  carpi  radialis  longus  above,  the  tendon 
of  the  pronator  teres  in  the  middle,  and  the  radius  interiorly  ; its  tendon  de- 
scends at  first  between  the  pronator  teres  and  extensor  radialis  longus,  after- 
wards between  the  latter  and  that  of  the  flexor  carpi  radialis  : at  its  insertion 
it  is  crossed  by  the  extensor  tendons  of  the  thumb.  This  muscle  and  its 
tendon  overlap  the  radial  nerve  and  vessels;  its  ulnar  edge,  therefore,  will 
serve  as  a guide  to  the  latter,  in  case  we  are  required,  during  life,  to  expose 
them,  in  order  to  tie  a ligature  around  the  radial  artery. 

Extensor  Carii  Radialis  Longus,  arises  tendinous  and  fleshy  from  the 
ridge  on  the  external  side  of  the  humerus,  between  the  supinator  longus  and 
the  external  condyle;  it  passes  over  the  outside  of  the  joint,  ends  in  aflat 
tendon,  which  descends  along  the  outer  and  back  part  of  the  radius,  runs 
through  a groove  on  its  lower  extremity,  and  passing  over  the  wrist  joint,  is 
inserted  into  the  back  part  of  the  carpal  end  of  the  metacarpal  bone  of  the 
index  finger.  Use , it  extends  the  wrist,  bends  the  hand  backwards,  and  ab- 
ducts it  a little;  it  may  also  assist  in  bending  the  elbow  joint ; it  is  covered 
by  the  last  muscle,  but  projects  behind  it;  the  tendon  passes  beneath  the 
extensors  of  the  thumb  and  the  annular  ligament;  it  covers  the  supinator 
brevis  and  the  following  muscle. 

Extensor  Carpi  Radialis  Brevis,  arises  tendinous  and  fleshy  from  the 
inferior  and  posterior  part  of  the  external  condyle,  and  from  the  external 
lateral  ligament,  descends  along  the  back  part  of  the  radius,  ends  in  a flat 
tendon,  which  runs  through  the  same  groove  as  the  tendon  of  the  last  muscle, 
beneath  which  it  lies  ; passes  also  beneath  the  annular  ligament,  and  is  inserted 
into  the  carpal  extremity  of  the  third  metacarpal  bone.  Use,  similar  to  that 
of  the  last;  it  is  covered  superiorly  by  the  last  described  muscle,  and  by  the 
supinator  longus,  and  below  by  the  tendons  of  the  extensor  muscles  of  the 
thumb,  and  by  that  of  the  last  muscle,  and  by  the  skin ; it  covers  the  supi- 
nator brevis  and  the  insertion  of  the  pronator  teres. 

Extensor  Digitorum  Communis,  is  situated  more  towards  the  back  part  of 
the  forearm  than  the  last  described  muscles;  it  arises  in  common  with  the 
last,  and  with  the  following,  from  the  external  condyle,  the  fascia,  and  its 
intermuscular  processes,  also  from  the  ulna;  it  descends,  and  about  the  mid- 
dle of  the  forearm  ends  in  four  tendons,  which  pass  under  the  annular  liga- 
ment in  a groove  in  the  radius,  extend  along  the  back  of  the  hand,  expanding 
as  they  approach  the  four' fingers,  into  the  phalanges  of  which  they  are  inserted 
by  a tendinous  expansion.  Use,  to  extend  all  the  joints  of  the  fingers:  this 
muscle  arises  between  the  extensor  carpi  radialis  brevis  and  extensor  ulnaris ; 
it  descends  superficially  between  these,  and  over  the  supinator  brevis  and 


68 


THE  DUBLIN  DISSECTOR, 


extensors  of  the  thumb ; on  the  back  of  the  hand  the  tendons  are  connected  to 
each  other  by  cross  slips ; that  which  goes  to  the  ring  finger  is  the  largest;  all 
the  tendons,  as  they  approach  the  base  of  the  first  phalanx,  become  thick  but 
narrow ; afterwards  they  enlarge  and  are  joined  by  the  tendons  of  the  luinbri- 
cales  and  interossei ; at  the  articulation  of  the  first  and  second  phalanx  each 
divides  into  three  bands;  the  middle  one  is  inserted  into  the  posterior  surface 
of  the  second  phalanx  ; the  lateral  pass  along  the  sides  of  this  articulation  ; 
they  afterwards  converge  and  unite  in  a flat  tendon,  which  is  inserted  into  the 
base  of  the  last  or  third  phalanx.  The  back  part  of  all  the  fingers  is  covered, 
as  far  as  the  last  phalanx,  by  a tendinous  expansion,  derived  from  these  ten- 
dons, and  from  those  of  the  lumbricales  and  interossei  muscles. 

Extensor  Carpi  Ulnaris,  arises  tendinous  and  fleshy  between  the  extensor 
communis  and  ancona^us,  ftom  the  external  condyle,  fascia  and  intermuscular 
septa;  descends  obliquely  inwards,  between  the  flexor  ulnaris  and  extensor 
communis,  towards  the  ulna,  and  receives  an  addition  from  it;  it  ends  in  a 
strong  tendon,  which  runs  through  a groove  on  the  back  of  the  ulna,  beneath 
the  annular  ligament,  and  is  inserted  into  the  carpal  end  of  the  fifth  metacar- 
pal bone.  Use,  to  extend  the  hand  and  bend  it  backwards;  also  to  adduct  it. 

Anconeus,  small,  triangular,  and  placed  at  the  outer  side  of  the  olecranon, 
beneath  the  skin ; arises  narrow  and  fleshy  from  the  posterior  and  inferior 
part  of  the  external  condyle,  forms  a thick  triangular  mass,  which  adheres  to 
the  synovial  membrane  and  descends  obliquely  inwards,  to  be  inserted  into 
the  external  surface  of  the.  olecranon,  and  about  the  superior  fifth  of  the  pos- 
terior surface  of  the  ulna.  Use , to  extend  the  forearm  on  the  arm,  and  to 
raise  the  synovial  membrane  out  of  the  articulation:  this  muscle  is  partly 
covered  by  the  tendon  and  aponeurosis  of  the  triceps ; the  remainder  of  it  is 
superficial ; it  is  situated  between  the  olecranon  and  the  extensor  carpi  ulnaris  ; 
it  often  appears  as  a continuation  of  the  triceps;  it  covers  the  articulation  of 
the  elbow  and  a portion  of  the  supinator  brevis. 

Extensor  Minimi  Digiti,  arises  in  common  with  the  last,  and  descends 
between  it  and  the  extensor  carpi  ulnaris;  it  forms  a small  fleshy  belly,  which 
descends  very  obliquely  inwards,  and  ends  in  a slender  tendon  ; this  passes 
through  a separate  groove  in  the  radius,  and  also  through  a distinct  division 
of  the  annular  ligament,  in  which  situation  it  is  frequently  found  divided  into 
two,  which  continue  in  contact,  and  afterwards  unite ; this  tendon  becomes 
attached  to  the  fourth  tendon  of  the  extensor  communis,  and  is  inserted  along 
with  it  into  the  posterior  part  of  the  phalanges  of  the  little  finger.  Use,  to 
assist  the  extensor  communis. 

The  deep  muscles  in  this  situation  will  be  exposed,  by  removing  the  super- 
ficial layer;  they  consist  of  the  supinator  radii  brevis,  three  extensors  of  the 
thumb,  and  the  indicator. 

Suitnator  Radii  Brevis,  short  and  flat,  surrounds  the  upper  part  of  the 
radius,  arises  from  the  external  condyle,  external  lateral  and  coronary  liga- 
ments, and  from  a ridge  on  the  outer  side  of  the  ulna,  which  commences  below 
its  lesser  sigmoid  cavity ; the  fibres  adhere  to  the  capsular  ligament,  and  de- 
scend obliquely  outwards  and  forwards  round  the  upper  part  of  the  radius, 
and  are  inserted  into  the  upper  third  of  the  external  and  anterior  surface  of 
this  bone,  from  above  its  tubercle  down  to  the  insertion  of  the  pronator  teres 
Use,  to  turn  the  radius  outwards,  so  as  to  make  the  hand  look  supine.  This 


OR  MANUAL  OF  ANATOMY. 


69 


muscle  is  covered  by  the  supinator  longus  and  radial  extensors  of  the  carpus 
externally;  by  the  anconaeus  and  extensor  ulnaris  posteriorly;  and  anteriorly 
by  the  radial  nerve  and  vessels,  and  by  the  brachiasus  and  biceps ; it  partly 
surrounds  the  humeral  and  ulnar  articulations  of  the  radius  ; its  anterior  edge 
is  notched  above  for  the  insertion  of  the  biceps,  and  is  overlapped  by  the  pro- 
nator teres  below. 

Extensor  Ossis  Metaoarpi  Pollicis,  or  Abductor  Pollicis,  arises  fleshy 
from  the  middle  of  the  posterior  part  of  the  ulna,  below  the  anconaeus,  also 
from  the  interosseous  ligament  and  posterior  surface  of  the  radius  below  the 
supinator  brevis ; it  descends  outwards  and  forwards,  and  ends  in  a tendon, 
which  passes  through  a groove  on  the  outside  of  the  lower  end  of  the  radiusr 
runs  by  the  side  of  the  carpus,  and  is  inserted  in  general  by  two  tendons,  one 
into  the  os  trapezium,  and  the  other  into  the  upper  and  back  part  of  the  meta- 
carpal bone  of  the  thumb.  Use,  to  extend  the  first  joint  of  the  thumb,  and 
separate  it  from  the  fingers  ; it  also  extends  the  wrist,  and  abducts  the  hand; 
it  can  also  assist  in  supination.  The  origin  of  this  muscle  is  concealed  by  the 
extensor  communis  and  carpi  ulnaris ; the  tendon  is  superficial,  and  passes 
over  the  tendons  of  the  common  extensor,  and  of  the  radial  extensors  of  the 
carpus,  also  over  the  radial  vessels. 

Extensor  Primi  Internodii  Pollicis,  or  Extensor  Minor,  arises  from  the 
back  part  of  the  ulna,  below  its  middle,  and  from  the  interosseous  ligament 
and  radius;  it  descends  along  the  radial  side  of  the  last  muscle:  its  tendon 
passes  through  the  same  groove  in  the  radius,  and  bound  down  by  the  same 
portion  of  the  annular  ligament,  and  is  inserted  into  the  posterior  part  of  the 
first  phalanx;  a small  slip  is  often  continued  on  to  the  second  phalanx.  Use , 
to  extend  the  second  joint  of  the  thumb,  and  to  assist  the  last  described  mus- 
cle; its  connections  are  also  similar. 

Extensor  Secundi  Internodii  Pollicis,  or  Extensor  Major,  arises  from 
the  posterior  surface  of  the  ulna  above  its  centre,  and  from  the  interosseous 
membrane ; its  belly  overlaps  the  two  former  muscles,  its  tendon  passes  along 
a distinct  groove  in  the  radius,  runs  over  the  outer  side  of  the  wrist,  the  meta- 
carpal bone  and  first  phalanx  of  the  thumb,  and  is  inserted  into  the  posterior 
part  of  the  second  or  last  phalanx.  Use,  to  extend  the  last  phalanx  of  the 
thumb  upon  the  first,  and  to  assist  the  former  muscles  in  extending  and  supi- 
nating  the  hand.  The  tendon  of  this  muscle  is  separated  from  the  two  former, 
on  the  outer  and  back  part  of  the  wrist,  by  a considerable  interval,  in  which 
we  perceive  the  tendons  of  the  radial  extensors  of  the  carpus,  and  the  radial 
artery ; the  relations  of  this  muscle  in  other  respects  are  nearly  similar  to 
those  of  the  other  extensors  of  the  thumb. 

Extensor  Indicis,  or  Indicator,  arises  from  the  middle  of  the  posterior 
surface  of  the  ulna  and  interosseous  membrane;  its  tendon  passes  under  the 
annular  ligament  along  with  those  of  the  common  extensor,  is  attached  to  the 
radial  side  of  that  tendou  which  belongs  to  the  forefinger,  and  is  inserted  along 
with  it  into  its  2d  and  3d  phalanges.  Use,  it  assists  the  common  extensor,  or 
produces  the  extension  of  the  forefinger  alone,  as  in  pointing.  This  muscle 
is  Concealed  by  the  extensor  communis  and  ulnaris,  lies  to  the  ulnar  side  of 
the  extensor  pollicis  major,  and  its  tendon  passes  under  those  of  the  common 
extensor.  Next  dissect  the  muscles  of  the  hand : first,  those  in  the  palm, 
which  consist,  externally,  of  the  muscles  of  the  thumb ; internally,  of  those 


ro 


THE  DUBLIN  DISSECTOR, 


of  the  little  finger,  and  in  the  middle  of  the  lumbricales  superficially,  and 
the  anterior  interossei,  deep  seated.  The  short  muscles  of  the  thumb  are  the 
abductor  pollicis,  opponens  pollicis,  flexor  pollicis  brevis,  adductor  pollicis, 
and  abductor  indicis. 

Abductor  Pollicis,  arises  broad  and  thin  from  the  anterior  part  of  the 
annular  ligament,  os  naviculare  and  trapezium,  inserted  into  the  outside  of  the 
base  of  the  1st  phalanx,  and  by  an  expansion  into  both  phalanges,  its  name 
implies  its  use,  to  separate  the  thumb  from  the  finger;  it  lies  superficial,  and 
is  most  external  of  Ihese  small  muscles. 

Opponens  Pollicis,  or  Flexor  Ossis  Metacarpi,  arises  from  the  annular 
liga,ment  and  os  naviculare  ; inserted  into  the  anterior  extremity  of  the  meta- 
carpal bone  of  the  thumb.  Use,  to  approximate  the  thumb  to  the  fingers;  it 
is  internal  to  and  overlapped  by  the  last  muscle ; it  lies  on  a part  of  the 
annular  ligament,  and  of  the  following  muscle. 

Flexor  Pollicis  Brevis,  consists  of  two  portions,  between  which  is  the 
tendon  of  the  flexor  longus  ; one  head,  the  external  or  anterior  arises  from 
the  inside  of  the  annular  ligament,  and  from  the  trapezium  and  scaphoid  bones, 
passes  outwards,  and  is  inserted  into  the  external  sesamoid  bone  and  base  of 
the  1st  phalanx  of  the  thumb;  the  2d,  or  internal  or  posterior  arises  from  the 
os  magnum,  and  the  base  of  the  metacarpal  bone  of  the  middle  finger;  it  also 
passes  outwards,  distinct  from  the  other  at  first,  but  afterwards  united  to  it, 
and  is  inserted  into  the  internal  sesamoid  bone,  and  base  of  the  1st  phalanx. 
Use,  to  flex  the  first  phalanx  and  metacarpal  bone  on  the  carpus  : this  muscle 
is  concealed  by  the  two  former,  and  by  the  first  lumbricalis  ; it  covers  the  two 
first  interossei  muscles,  and  the  tendon  of  the  flexor  carpi  radialis  ; its  outer 
edge  is  connected  to  the  opponens  pollicis,  and  the  internal  to  the  adductor. 

Adductor  Pollicis,  triangular  and  broad,  arises  fleshy  from  three-fourths 
of  the  anterior  surface  of  the  third  metacarpal  bone,  the  fibres  pass  outwards 
over  the  second  metacarpal,  and  converging  are  inserted  into  the  inner  side  of 
the  root  of  the  first  phalanx  of  the  thumb,  along  with  part  of  the  last  muscle  ; 
its  name  denotes  its  use.  This  muscle  at  its  origin  is  covered  anteriorly  by 
the  deep  flexor  tendons  and  by  the  lumbricales  ; its  insertion  is  covered  by 
the  following  muscle,  which  may  be  best  seen  from  behind. 

Abductor  Indigis,  also  triangular,  arises  tendinous  and  fleshy  from  the 
metacarpal  bone  of  the  forefinger,  and  from  one  half  of  that  of  the  thumb: 
its  fibres  extend  obliquely  inw:ardsand  forwards,  end  in  a tendon  which  passes 
by  the  outer  side  of  the  first  joint  of  the  forefinger,  and  is  inserted  into  the 
outer  side  of  the  base  of  its  first  phalanx.  Use,  to  separate  the  forefinger  from 
the  others,  or  to  adduct  the  thumb.  This  muscle  is  superficial  posteriorly; 
anteriorly  it  is  covered  by  that  last  described  : the  radial  artery  passes  between 
its  two  heads  or  origins;  this  muscle  is  similar  to,  and  may  be  regarded  as 
one  of  the  posterior  interossei,  like  these  also,  its  insertion  joins  that  of  the 
common  extensor  tendon.  In  the  middle  of  the  palm  of  the  hand  are  seen 
four  small  muscles. 

Lumbricales,  arise  from  the  outer  side  of  the  tendons  of  the  flexor  pro- 
fundus, near  (he  carpus,  a little  beyond  the  annular  ligament ; they  each  form 
a small  fleshy  belly,  which  ends  in  a tendon;  this  runs  along  the  radial  side 
of  the  finger,  joins  the  tendon  of  the  corresponding  interosseous  muscle,  and 
is  inserted  about  the  middle  of  the  first  phalanx  into  the  tendinous  expansion 


OR  MANUAL  OF  ANATOMY. 


71 


which  covers  the  back  part  of  each  finger.  Use,  to  assist  in  bending  the  first 
joint  of  the  finger;  they  cannot  act  unless  the  flexors  are  tense;  they  can 
also  adduct  and  abduct  the  fingers,  and  when  the  common  extensor  muscle 
is  in  action,  they  may  assist  in  extending  them;  these  small  muscles  are 
covered  by  the  superficial  flexor  tendons,  palmar  vessels  and  nerves : the  first 
is  the  largest,  the  fourth  the  smallest;  the  two  middle  run  nearly  parallel, 
but  the  internal  and  external  diverge  ; the  tendons  of  the  lumbricales  fre- 
quently divide  into  two  portions ; one  of  these  will  be  inserted  into  the  first 
phalanx,  the  other  into  the  posterior  tendinous  expansion.  On  the  inner  side 
of  the  palm  of  the  hand  are  the  three  following  muscles,  which  belong  to  the 
little  finger. 

Abductor  Minimi  Digiti,  arises  fleshy  from  the  annular  ligament  and  from 
the  pisiform  bone ; its  fibres  run  along  the  ulnar  side  of  the  metacarpal  bone, 
and  are  inserted  tendinous  into  the  ulnar  side  of  the  1st  phalanx;  its  name 
implies  its  use  ; it  is  superficial ; a few  fibres  of  the  palmaris  only  cover  it; 
its  origin  is  partly  continuous  with  the  insertion  of  the  flexor  carpi  ulnaris. 

Flexor  Brevis  Minimi  Digiti,  arises  from  the  annular  ligament  and  unci- 
form bone,  inserted  by  a round  tendon  into  the  base  of  the  first  phalanx  of 
the  little  finger.  Use,  to  flex  and  adduct  the  little  finger ; it  lies  to  the  radial 
side  of  the  last  muscle,  along  with  which  it  is  inserted. 

Adductor,  or  Opponens  Minimi  Digiti,  arises  internal  to  the  last,  and  over- 
lapped by  it,  and  is  inserted  into  all  the  metacarpal  bone  of  this  finger:  its 
name  denotes  its  use. 

When  all  the  flexor  and  extensor  tendons  have  been  removed,  we  observe 
the  intervals  between  the  metacarpal  bones  to  be  filled  by  muscular  fibres, 
which  are  called  the  interosseous  muscles  ; they  are  divided  into  two  planes, 
a posterior  and  an  anterior.  The  Interossei  Antici,  or  Interni  or  Palmares 
are  four  in  number;  they  arise  from  the  sides  of  the  metacarpal  bones, 
and  are  inserted  into  the  first  phalanges,  and  into  the  tendinous  expansion 
which  covers  the  dorsum  of  each  finger : the  1st  or  prior,  or  externus  indicis, 
arises  from  the  radial  side  of  the  second  metacarpal  bone,  and  is  inserted  into 
the  external  side  of  the  first  phalanx  of  the  forefinger.  Use,  to  abduct  the 
forefinger;  the  2d  or  posterior,  or  internus,  or  adductor  indicis,  arises  from 
the  ulnar  side  of  the  second  metacarpal  bone,  and  is  inserted  into  the  inner 
side  of  the  first  phalanx  of  the  forefinger ; 3d  or  prior,  or  externus  or  adductor 
annularis  arises  from  the  radial  side  of  the  fourth  metacarpal  bone,  and  is 
inserted  into  the  external  side  of  the  first  phalanx  of  the  ring  finger.  Use, 
to  draw  the  ring  finger  towards  the  thumb : the  4th,  or  abductor  minini  digiti 
arises  from  the  radial  side  of  the  fifth  metacarpal  bone,  and  is  inserted  into 
the  outside  of  the  1st  phalanx  of  the  little  finger.  Use,  to  draw  the  little 
finger  towards  the  thumb. 

The  Posterior  Interossei,  are  seen  on  the  back  part  of  the  hand  ; they  are 
longer  than  the  anterior : they  each  arise  by  two  sets  of  fibres  from  the  opposed 
sides  of  two  metacarpal  bones,  and  are  inserted  into  the  base  of  the  first 
phalanx  of  each  finger,  and  into  the  posterior  tendinous  expansion  : the  1st, 
or  prior,  or  externus  medii,  arises  from  the  second  and  third  metacarpal 
bones,  fills  the  space  between  these  two,  and  is  inserted  into  the  outer  side  of 
the  base  of  the  1st  phalanx  of  the  middle  finger.  Use,  to  draw  the  middle 
finger  towards  the  thumb:  the  2d,  or  externus  medii  is  situated  between  the 


72 


THE  DUBLIN  DISSECTOR, 


metacarpal  bones  of  the  middle  and  ring  finger,  and  is  inserted  into  the  inner 
side  of  the  first  phalanx  of  the  middle  finger.  Use,  to  draw  the  middle 
towards  the  ring  finger;  the  3d,  or  externus  annularis,  is  between  the  4th 
and  5th  metacarpal  bones ; and  is  inserted  into  the  inner  side  of  the  ring 
finger.  Use,  to  draw  the  ring  finger  inwards.  All  these  muscles  can  also 
extend  the  fingers.  Some  consider  the  dorsal  interossei  as  four  in  number, 
making  the  abductor  idicis  the  first  of  this  class. 

In  the  dissection  of  the  forearm  and  hand,  we  meet  with  the  branches  of 
the  brachial  artery,  with  their  accompanying  veins;  also  branches  of  the 
brachial  plexus  of  nerves ; the  cutaneous  veins  have  been  already  noticed. 
The  brachial  artery,  when  it  arrives  at  the  head  of  the  elbow,  divides  into  its 
radial  and  ulnar  branches.  The  radial  artery  descends  from  the  elbow 
obliquely  outwards,  to  the  styloid  process  of  the  radius,  passes  over  the  outer 
side  of  the  carpus  and  then  between  the  metacarpal  bones  of  the  thumb,  and  of 
the  forefinger,  where  it  divides  into  three  branches,  radialis  indicis,  magna  polli- 
cis,  and  palmaris  profunda : the  radial  artery  at  first  lies  between  the  pronator 
teres  and  supinator  longus;  afterwards  between  the  supinator  and  flexor 
carpi  radialis ; it  then  winds  round  the  carpus,  over  the  external  lateral  lig- 
ament, and  beneath  the  extensor  tendons  of  the  thumb;  in  the  forearm  it  is 
only  overlapped  above  by  the  supinator  longus ; in  the  rest  of  its  course  it  is 
superficial ; it  is  accompanied  by  two  veins,  and  by  the  radial  branches  of  the 
muculo-spiral  nerve,  which  lies  to  its  outer  side.  The  radial  artery  gives  off, 
1st,  The  recurrent  branch,  which  ascends  in  front  of  the  external  condyle, 
to  supply  the  muscles  attached  there,  and  to  inosculate  with  the  superior  pro- 
funda; 2d,  in  its  course  down  the  forearm,  several  musclar  branches;  3d, 
near  the  wrist,  the  superficial  is  volse,  which  passes  to  the  small  muscles  of  the 
thumb,  and  communicates  with  the  superficial  palmar  artery  ; 4th  and  5th, 
branches  to  the  fore  and  back  part  of  the  carpus  : and  between  the  thumb  and 
index  finger  it  divides  into  its  three  last  branches  ; the  magni  pollicis  subdi- 
vides, and  supplies  the  sides  of  the  thumb  ; the  radialis  indicis,  in  like  manner, 
supplies  the  forefinger;  and  the  palmaris  profunda  passes  beneath  all  the 
flexor  tendons  across  the  four  metacarpal  bones,  forms  the  deep  palmar  arch, 
and  then  joins  a branch  from  the  ulnar  artery.  The  ulnar  artery  is  larger 
than  the  radial ; it  descends  obliquely  inwards,  beneath  the  superficial  flexors 
and  pronators,  and  lies  on  the  flexor  profundus;  it  passes  over  the  annular 
ligament  into  the  palm  of  the  hand,  and  there  divides  into  a superficial  and 
deep  branch  : this  vessel  is  covered  above  by  several  muscles,  inferiorly  it  is 
superficial,  and  lies  between  the  tendon  of  the  flexor  sublimis  and  flexor  carpi 
ulnaris;  it  is  attended  by  its  two  veins,  and  in  the  inferior  two-thirds  of  the 
forearm  by  the  ulnar  nerve,  which  always  lies  to  its  ulnar  side ; near  the  wrist 
this  nerve  is  somewhat  behind  the  artery.  The  ulnar  artery  sends  off  1st  and 
2d  its  recurrent  branches,  the  anterior,  small,  ascends  in  front  of  the  internal 
condyle,  the  posterior,  large,  passes  behind  that  condyle  and  joins  the  inferior 
profunda;  3d,  the  interosseous  artery,  which  passing  backwards,  divides  into 
its  posterior  and  anterior  branch  ; the  posterior  passes  through  the  upper  part 
of  the  interosseous  space,  and  ascends  in  the  substance  of  the  anconaeus  ; the 
anterior  interosseous  descends  between  and  beneath  the  flexor  profundus  and 
flexor  pollicis  as  far  as  the  pronator  quadratus,  where  it  terminates ; 4th, 
muscular  branches  ; 5th  and  6th,  to  the  back  and  front  of  the  carpus  ; and  in 


OR  MANUAL  OF  ANATOMY. 


73 


the  palm  of  the  hand  it  terminates  in  the  deep  and  superficial  branch  ; the 
former  sinks  between  the  muscles  of  the  little  finger,  to  join  the  deep  palmar 
arch ; the  superficial  runs  across  the  flexor  tendons,  forming  the  superficial 
arch,  from, the  convex  side  of  which,  the  long  digital  arteries  arise;  these 
supply  the  three  inner  fingers.  (See  Vascular  System.) 

In  addition  to  the  cutaneous  nerves  already  noticed,  we  find  the  median, 
ulnar  and  musculo-spiral  decending  in  the  forearm;  the  median  nerve  passes 
between  the  heads  of  the  pronator  teres,  and  descends  beneath  the  flexor  sub- 
limis,  giving  off  the  anterior  interosseous  nerve,  and  branches  to  the  muscles 
of  the  forearm;  it  passes  beneath  the  annular  ligament,  appears  superficial 
in  the  palm  of  the  hand  near  the  thumb,  and  sends  off  digital  branches,  which 
accompany  the  digital  arteries  to  all  the  fingers,  except  the  little  and  the  ul- 
nar side  of  the  ring  finger.  The  ulnar  nerve  winds  round  behind  the  inter- 
nal condyle,  between  the  heads  of  the  flexor  carpi  ulnaris,  and  descends  along 
the  internal  side  of  the  ulnar  artery  to  the  hand,  where  it  terminates,  by  di- 
viding into  a small  superficial  and  a large  deep  branch.  The  musculo-spiral 
or  radial  nerve  is  seen  beneath  the  supinator  longus,  decending  along  the 
outer  side  of  the  radial  artery,  and  supplying  the  adjacent  muscles  ; near  the 
elbow  it  gives  off  the  posterior  interosseous  nerve  and  a little  below  the  mid- 
dle of  the  forearm  it  passes  beneath  the  tendon  of  the  supinator,  and  becomes 
cutaneous,  being  distributed  to  the  integuments  of  the  thumb  and  back  of  the 
hand.  (See  Anatomy  of  the  Nervous  System.) 


CHAPTER.  VI. 

DISSECTION  OF  THE  ABDOMEN. 

§ 1. — Of  the  Muscles  on  the  Anterior  and  Lateral  Parts  of  the  Abdomen. 

Divide  the  integuments  from  the  sternum  to  the  pelvis,  from  the  crest  of 
the  ilium  on  each  side  to  the  umbilicus,  also  from  this  point  upwards  and 
outwards  on  each  side  over  the  cartilages  of  the  9th  and  10th  ribs,  as  high  as 
midway  between  the  axilla  and  the  border  of  the  thorax ; dissect  of  the  flaps  ; 
the  subcutaneous  cellular  membrane  will  be  found  dense  and  strong,  so  as  to 
have  receiyed  the  name  of  superficial  fascia ; this  may  be  removed  along 
with  the  integuments  from  the  superior  and  lateral  parts  of  the  abdomen,  but 
interiorly  and  anteriorly  it  may  be  suffered  to  remain  for  further  examina- 
tion, a knowledge  of  its  structure  and-  connections  being  of  practical  impor- 
tance in  the  disease  of  hernia.  The  superficial  fascia  is  continued  from 
the  surface  of  the  thorax,  over  the  abdominal  muscles ; weak  and  thin  above, 
it  increases  in  density  as  it  descends;  from  the  abdomen  it  extends  on  either 
side  over  Pou part’s  ligament  to  the  thigh,  which  it  invests,  and  in  the  centre 
over  the  organs  of  generation;  in  the  male  a process  of  it  passes  round  the 
spermatic  cord  on  each  side,  decends  into  the  scrotum,  and  is  continuous  with 
the  facia  of  the  perineum,  and  from  the  linea  alba  a thick  portion  runs  to  the 
dorsum  cf  the  penis,  invests  this  organ,  and  serves  as  a suspensory  ligament 
to  it.  In  the  female  it  is  loaded  with  fat  in  this  situation,  and  descends  into 
the  labia.  As  this  fascia  passes  over  Poupart’s  ligament,  it  is  connected  to  it, 
through  the  medium  of  a thin  but  dense  membrane,  which  ascends  from  the 
10 


74 


THE  DUBLIN  DISSECTOR, 


fascia  lata  of  the  thigh,  and  is  soon  lost  on  the  abdominal  muscles ; to  this  the 
superficial  fascia  is  attached,  so  as  to  give  the  latter  the  appearance  of  ad- 
hering to  Poupart’s  ligament,  although  it  really  is  not  so.  About  an  inch 
below  this  ligament,  in  the  groin,  the  superficial  adheres  intimately  to  the  fascia 
lata;  in  this  situation  the  former  is  very  thick  and  laminated,  forming  cap- 
sules for  the  inguinal  lymphatic  glands,  and  is  connected  to  the  facia  lata  bv 
vessels  and  nerves  which  perforate  the  latter  in  their  course  to  and  from  these 
glands,  the  superficial  fascia  and  integuments  ; the  facia  lata  here  also  is  very 
weak,  and  rather  cellular,  so  that  the  superficial  and  deep  fasciae  are  continu- 
ous or  identified  in  this  situation;  soon  afterwards,  however,  they  become 
distinct.  The  superficial  fascia  is  thinner  along  the  sides  than  it  is  on 
the  forepart  of  the  abdomen  ; its  cutaneous  surface  is  cellular,  and  closely  con- 
nected to  the  integument;  its  posterior  surface  is  more  compact  and  smooth  ; 
several  blood  vessels  ramify  between  the  skin  and  this  membrane ; three  set 
on  each  side,  viz.  the  external  circumflex  ilii,  external  epigastric  and  exter- 
nal pudic  arteries;  these  all  arise  in  the  groin,  from  the  femoral  artery,  or 
from  some  of  its  branches,  and  ascend  over  Poupart's  ligament;  the  first 
ramifies  towards  the  anterior  spineous  process  of  the  ilium  ; the  second,  which 
is  the  largest  of  the  three,  ascends  towards  the  umbilicus,  and  the  third  passes 
transversely  towards  the  pubis;  these  several  arteries  supply  the  integu- 
ments, and  inosculate  with  the  deep  seated  vessels  of  the  same  names;  they 
are  each  accompanied  by  one  or  two  veins,  which  are  often  found  remarkably 
tortuous.  The  superficial  fascia  supports  and  connects  the  fleshy  and  tendi- 
nous fasciculi  of  the  abdominal  muscles ; it  aLso  possesses  a good  deal  of  elas- 
ticity, which  assists  these  muscles  in  the  contraction  of  the  parietes  of  the  ab- 
domen. Remove  the  integuments  and  facia  from  the  surface  of  the  abdominal 
muscles,  and  continue  the  dissection  as  far  back  as  within  two  or  three  inches 
of  the  spine.  In  dissecting  the  external  oblique  muscle  at  its  upper  and  an- 
terior part,  care  must  be  taken  not  to  raise  its  aponeurosis,  which  is  so  thin, 
as  it  passes  over  the  anterior  part  of  the  thorax,  that  it  may  be  mistaken  for 
condensed  cellular  membrane.  In  order  to  expose  the  external  oblique  mus- 
cle, make  its  fibres  tense  by  putting  a block  under  the  loins,  and  dissect  in  a 
line  nearly  parallel  to  its  fibres;  to  clean  the  posterior  portion,  the  subject 
should  be  turned  a little  to  the  opposite  side.  The  abdominal  muscles  con- 
sist of  five  pair,  viz.  obliqui  externi  and  interni,  transversales,  recti,  and 
pyramidales. 

Obuquus  Externus,  or  Descenders,  broad,  thin,  and  somew  hat  square, 
extends  over  the  anterior  and  lateral  parts  of  the  abdomen,  fleshy  above  and 
behind,  tendinous  before  and  below;  it  arises  by  eight  or  nine  triangular 
fleshy  slips;  sometimes  there  are  only  seven,  from  the  eight  or  nine  inferior 
ribs,  at  a little  distance  from  their  cartilages  ; the  five  superior  indigitate  w ith 
corresponding  portions  of  the  serratus  magnus;  and  the  three  inferior  w ith 
those  of  the  latissimus  dorsi,  by  which  they  are  a little  overlapped.  The 
superior  fibres  are  thin,  aponeurotic,  and  weak,  and  pass  horizontally  inw  ards ; 
a tendinous  and  fleshy  slip  often  connects  this  portion  to  the  great  pectoral 
muscle:  the  middle  are  the  longest,  and  descend  obliquely  forwards  and 
inwards : the  posterior  are  strong  and  fleshy,  and  descend  almost  vertically  : 
the  superior  and  middle  fibres  end  in  a broad  tendon,  which  commences  at  a 
little  distance  external  to  the  linea  semilunaris ; this  tendon  is  continued 
over  the  forepart  of  the  abdomen,  covers  the  rectus  muscle,  and  is  so  broad 


OR  MANUAL  OF  ANATOMY. 


75 


inferiorly  as  to  extend  from  one  spine  of  the  ilium  to  that  of  the  opposite  side  ; 
it  is  very  strong  inferiorly,  but  so  very  thin  above,  where  it  covers  the  tho- 
racic portion  of  the  rectus,  that  the  inexperienced  dissector  often  removes  it 
along  with  the  integuments.  The  external  oblique  is  inserted  tendinous  into 
the  ensiform  cartilage,  linea  alba,  pubis,  Pou part’s  ligament  which  is  formed 
by  this  tendon,  and  into  the  anterior  superior  spinous  process  of  the  ilium, 
also  tendinous  and  fleshy  into  the  outer  edge  of  the  two  anterior  thirds  of  the 
crest  of  the  ilium.  Use,  to  depress  the  ribs,  and  compress  the  abdominal 
viscera,  so  as  to  assist  in  expiration,  and  in  the  evacuation  of  the  urine  and 
feces.  When  both  muscles  act,  they  can  bend  the  trunk  forwards;  if  one 
only  act,  it  will  bend  it  to  that  side,  and  it  may  also  rotate  it  to  the  opposite 
side.  This  muscle  is  covered  by  the  skin  and  superficial  fascia,  its  posterior 
border  is  sometimes  overlapped  by  the  latissimus  dorsi ; in  some  cases,  how- 
ever, these  muscles  do  not  meet,  and  a small  part  of  the  internal  oblique  is 
seen  in  the  triangular  space  between  them.  On  the  dissected  tendons  of 
this  pair  of  muscles,  we  may  remark  the  following  particulars  : the  linea  alba 
and  umbilicus,  lineae  semilunares,  linte  transverse,  the  external  abdominal  or 
inguinal  rings,  and  Poupart’s  ligament  on  each  side.  The  linea  alba  is  a 
dense  ligamentous  cord,  extending  from  the  ensiform  cartilage  to  the  upper 
part  of  the  symphisis  pubis;  it  is  formed  by  the  intimate  union,  or  by  the 
crossing  of  the  tendinous  fibres  of  the  muscles  of  opposite  sides  ; its  greatest 
breadth  is  at  the  umbilicus,  from  this  to  the  pubis  it  decreases;  its  superior 
portion  is  much  broader  than  its  inferior : the  integuments  are  more  closely 
connected  to  this  line,  than  they  are  at  either  side  ; hence  the  more  fat  the 
subject,  the  more  indented  will  the  skin  appear  along  it.  About  the  centre 
of  the  linea  alba  is  the  umbilicus;  this,  in  the  foetus,  was  a foramen,  through 
which  were  transmitted  the  umbilical  vein  from  the  mother,  and  the  umbilical 
arteries  and  the  urachus  from  the  child  : before  the  integuments  were  removed, 
this  spot  appeared  depressed,  particularly  if  the  subject  has  been  very  fat;  it 
now  projects,  and  seems  formed  of  very  dense  cellular  tissue,  surrounded  bv, 
and  connected  to  the  adjacent  tendinous  fibres. 

The  linea  alba  serves  as  a fixed  point  for  the  oblique  and  transverse  muscles 
on  either  side,  also  as  a ligament  to  connect  the  thorax  to  the  pelvis,  and  to 
support  the  former  when  bending  the  tru nk  backwards  so  as  to  resist  or  prevent 
too  forcible  extension  of  the  spine.  In  the  inferior  part  of  this  line  some 
practitioners  recommend  the  following  operations  to  be  performed : punc- 
turing the  bladder  in  case  of  retention  of  urine;  pracentesis,  or  tapping  of 
the  abdomen,  in  case  of  ascites;  and  the  superior  operation  for  lithotomy. 

The  inferior  fourth  or  fifth  part  of  the  linea  alba  is  sometimes  deficient,  as 
also  a portion  of  the  muscles  on  each  side;  so  that  the  urinary  bladder  is 
superficial,  and  constantly  exposed : in  such  cases  the  anterior  part  of  this 
viscus  also  is  usually  wanting,  and  therefore  its  cavity  and  the  orifices  of  the 
ureters  can  be  perceived  during  life. 

The  linea  semilunaris  extends  from  the  tuberosity  of  the  pubis  on  each 
side  upwards  and  outwards,  about  four  inches  from  the  linea  alba,  towards 
the  cartilages  of  the  8th  and  9th  ribs;  it  appears  white,  and  somewhat  de- 
pressed, and  is  formed  by  the  tendon  of  the  internal  oblique,  dividing  at  the 
edge  of  the  rectus  into  two  layers,  to  enclose  this  muscle  in  a sort  of  sheath. 
In  the  living  subject  this  line  maybe  traced  by  taking  the  point  midway 


76 


THE  DUBLIN  DISSECTOR, 


between  the  umbilicus  and  the  anterior  superior  spinous  process  of  the  ilium, 
and  from  it  drawing  one  line  towards  the  tuberosity  or  spine  of  the  pubis, 
and  another  towards  the  cartilage  of  the  9th  rib.  The  operation  of  tapping 
ovarian  dropsy  should  always  be  performed  here;  and  this  situation  is  also 
selected  by  some  as  the  best  for  performing  paracentesis  in  case  of  ascites.  In 
this  last  mentioned  disease,  however,  this  line  is  not  exactly  midway 
between  the  umbilicus  and  spine  of  the  ilium,  but  half  an  inch  nearer  the 
latter. 

The  linese  transversal  are  three  or  four  in  number,  and  cross  the  rectus 
muscle  from  the  linea  alba  to  the  linea  semilunaris;  they  are  tendinous  inter- 
sections of  that  muscle,  which  adhere  so  intimately  to  its  sheath,  as  to  give  to 
the  latter  this  indented  appearance.  These  lines  will  be  again  noticed  in  the 
dissection  of  the  rectus ; they  are  much  better  marked  in  some  than  in  others: 
during  life  they  are  very  distinct  when  the  abdominal  muscles  are  in  strong 
action.  Between  the  linea  alba  and  semilunaris  on  each  side  many  small 
holes  are  often  to  be  observed  in  the  tendon  of  the  external  oblique:  they  are 
only  for  the  transmission  of  small  vessels  and  nerves:  they  are  generally  of 
a square  form,  and  are  much  larger  and  more  numerous  in  some  than  in  others. 
External  and  superior  to  the  pubis  on  each  side  we  may  always  remark  the 
opening  called  the  external  inguinal  or  abdominal  ring,  transmitting  in  the 
male  subject  the  spermatic  vessels  and  cremaster  muscle,  and  in  the  female 
the  round  ligament  of  the  uterus.  This  opening  is  of  a triangular  form,  the 
base  at  the  pubis,  the  apex  is  superior  and  external ; the  sides  are  called  the 
pillars  of  the  ring,  one  of  which  is  superior,  internal,  and  anterior;  the  other 
or  Poupart’s  ligament,  is  inferior,  external,  and  posterior  : the  first,  or  supe- 
rior pillar,  is  broad,  and  inserted  into  the  symphysis  and  into -the  opposite 
pubis  ; some  fibres  are  continuous  with  the  fascia  lata  of  the  opposite  thigh  ; 
this  pillar  decussates  with  that  of  the  opposite  side,  on  the  forepart  of  the 
pubis,  and  both  send  fibres  to  the  dorsum  of  the  penis;  the  inferior  pillar  is 
the  internal  or  pubic  portion  of  Poupart’s  ligament:  the  apex  of  this  open- 
ing is  rounded  by  a series  of  fibres,  which  serve  to  connect  the  pillars  to  each 
other.  These  fibres  arise  from  Poupart’s  ligament  at  a little  distance  from 
the  spine  of  the  ilium,  pass  in  curved  lines  upwards  and  inwards  across  the 
upper  part  of  the  ring,  and  are  lost  on  the  surface  of  the  tendon;  they  serve, 
by  preventing  the  separation  of  the  sides  of  the  ring,  to  protect  this  part  of 
the  abdomen  against  a protrusion  of  its  contents.  These  fibres  are  in  some 
cases  so  closely  connected,  as  to  merit  the  name  of  a fascia  (the  intercolumnal 
fascia);  this,  in  old  cases  of  hernia,  has  been  found  of  great  strength,  and 
prolonged  for  some  distance  on  the  hernial  sac,  and  intimately  connected  with 
the  cremaster  muscle;  it  is  this  fascia,  or  these  intercolumnal  bands,  that 
obscure  this  opening  in  many  cases,  and  deprive  it  of  that  defined  figure 
usually  mentioned  by  writers,  or  delineated  in  plates;  the  tendon  of  the 
external  oblique  is  alone  concerned  in  the  formation  of  the  external  abdominal 
ring,  there  being  no  corresponding  deficiency  in  the  internal  oblique  or  trans- 
verse muscle;  the  spermatic  cord,  or  round  ligament,  must  therefore  take  an 
oblique  course  to  arrive  at  this  opening;  this  will  be  seen  in  the  next  stage 
of  the  dissection. 

Poup art's  or  Fallopius’  ligament  or  the  crural  arch,  is  the  inferior  thickened 
edge  of  the  tendon  of  the  external  oblique  : it  is  very  strong,  and  when  the 


OR  MANUAL  OF  ANATOMY. 


lower  extremity  is  extended,  and  the  foot  and  toes  everted,  it  appears  very 
tense ; if  we  consider  it  as  a distinct  ligament,  it  may  be  described  as  having 
an  attachment  to,  or  as  arising  from  the  anterior  superior  spinous  process  of 
the  ilium,  and  thence  descending  obliquely  forwards  and  inwards  to  the  pubis, 
into  which  it  is  inserted  by  two  attachments,  one  anteriorly  into  the  tuberosity 
of  spine  ; the  other  posteriorly  into  the  linea  injiominata  of  the  pubis,  or  the 
commencement  of  the  linea  ileo-pectinea : the  1st  or  iliac  end  of  Poupart’s 
ligament  is  broad  and  continuous  above,  with  the  tendon  of  the  oblique,  and 
below  with  the  fascia  lata ; the  anterior  portion  of  the  pubal  end  or  the  second 
insertion,  is  distinct  and  round,  and  can  be  felt  through  the  skin ; it  lies  be- 
hind the  cord,  and  is  connected  to  that  portion  of  the  fascia  lata  which  covers 
the  adductor  muscles ; the  posterior  pubal  attachment  or  the  third  insertion, 
also  called  Gimbernaut’s  ligament , is  broad  and  thin,  and  lies  superior, 
posterior,  and  external  to  the  former;  it  may  be  seen  by  raising  the  cord  out 
of  the  external  ring,  and  everting  Poupart’s  ligament  a little  ; it  is  of  a tri- 
angular form,  the  apex  is  anterior  towards  the  tuberosity  or  spine  of  the  pubis; 
the  base  is  external  and  posterior,  somewhat  crescentic,  looking  towards  the 
femoral  vessels ; to  it  some  fibres  from  the  outer  or  iliac  part  of  the  fascia  lata 
are  attached,  so  as  to  elongate  it  in  this  direction : this  third  insertion  of  Pou- 
part’s ligament  forms  the  internal  boundary  of  the  femoral  ring,  and  is  there- 
fore concerned  in  the  anatomy  of  femoral  hernia,  as  will  be  seen  hereafter. 
Poupart’s  ligament  owes  much  of  its  strength  to  its  connection  with  the  fascia 
lata  of  the  thigh,  as  may  be  seen  at  present,  also  to  its  attachment  to  the  fascia 
transversalis  and  iliaca,  which  will  be  exposed  in  a future  stage  of  the  dissec- 
tion. Poupart’s  ligament  is  of  use  in  strengthening  the  inferior  part  of  the 
abdomen,  and  affording  a fixed  point  of  attachment  to  the  deeper  muscles  and 
to  the  different  aponeuroses ; it  also  protects  the  great  femoral  vessels  and 
nerves  in  their  passage  from  the  abdomen  to  the  thigh,  and  its  third  insertion 
partly  fills  up  the  internal  portion  of  the  crural  arch.  From  this  third  inser- 
tion, and  from  the  pubis,  a band  of  fibres  may  be  observed  to  pass  upwards 
and  inwards  behind  the  superior  pillar  of  the  ring  towards  the  linea  alba ; these 
assume  in  general,  a triangular  shape,  and  have  received  the  name  of  the  tri- 
angular ligament  or  fascia ; the  base  is  interiorly  at  the  linea  ileo-pectinea ; 
the  apex  is  superior  and  internal  towards  the  linea  alba,  and  is  continuous 
with  the  external  oblique  tendon  of  the  opposite  side  : this  fascia  serves  to 
protect  the  abdomen  in  this  region.  Raise  the  external  oblique,  by  dissecting 
off  its  serrated  origins  from  the  ribs,  detach  also  its  insertion  from  the  crest  of 
the  ilium,  and  from  the  internal  oblique  muscle,  cleaning,  at  the  same  time, 
the  surface  of  the  latter;  throw  the  external  oblique  towards  the  opposite  side, 
separating  it  as  far  forward  as  its  connections  will  permit,  that  is  about  half  an 
inch  internal  to  the  linea  semilunaris  ; divide  its  tendon  transversely  from  the 
spine  of  the  ilium,  towards  the  lower  third  of  the  rectus,  about  an  inch  above 
the  external  ring,  thus  preserving  Poupart’s  ligament  and  the  external  ring  for 
further  examination,  in  relation  to  the  anatomy  of  hernia.  When  the  ex- 
ternal oblique  is  raised,  we  see  the  inferior  ribs,  the  inferior  intercostal  mus- 
cles, the  internal  oblique,  and  the  cremaster. 

Obliques  Internus,  or  Ascendens,  is  also  situated  at  the  anterior  and 
lateral  part  of  the  abdomen,  broader  before  than  behind,  and  more  fleshy  be- 
low than  above  ; it  arises  tendinous,  but  soon  becomes  fleshy,  from  the  fascia 


78 


THE  DUBLIN  DISSECTOR, 


lumborum,  from  all  the  crest  of  the  ilium,  and  from  the  external  third  or  fourth 
of  Poupart’s  ligament,  the  fibres  diverge  in  a radiated  manner ; those  from  the 
lumbar  fascia  and  posterior  part  of  the  ilium  ascend  obliquely  forwards ; those 
from  the  anterior  part  of  the  ilium  pass  transversely,  and  those  from  Poupart’s 
ligament  descend  obliquely  inwards ; the  fibres  continue  fleshy  further  for- 
ward than  those  of  the  external  oblique  ; at  the  linea  semilunaris  thev  end  in 
a flat  tendon,  which  at  the  edge  of  the  rectus  divides  into  two  layers  to  enclose 
this  muscle;  the  anterior  is  united  to  the  tendon  of  the  external  oblique,  the 
posterior  and  thinner  layer  is  joined  to  the  tendon  of  the  transversalis ; about 
midway  between  the  umbilicus  and  the  pubis,  the  tendon  of  the  internal  oblique 
does  not  divide,  but  the  whole  passes  in  front  of  the  rectus,  along  with  the 
tenon  of  the  transversalis,  to  which  it  is  closely  connected  ; a little  above  the 
pubis  these  two  tendons  are  inseparably  joined,  and  are  called  the  conjoined 
tendons.  The  internal  oblique  is  inserted,  tendinous  and  fleshy  into  the  car- 
tilages of  the  seven  inferior  ribs,  tendinous  into  the  ensiform  cartilage,  and 
into  the  whole  length  of  the  linea  alba ; the  conjoined  tendons  are  inserted 
into  the  symphisis  and  upper  edge  of  the  pubis,  and  passing  external  to  the 
rectus  are  also  inserted  into  the  linea  innominata,  where  they  are  connected 
with  Gimbernaut’s  ligament,  and  inseparably  joined  to  the  fascia  transversalis ; 
these  conjoined  tendons  lie  posterior  to  the  spermatic  cord  and  to  the  trian- 
gular ligament,  and  afford  much  security  to  that  part  of  the  abdomen  behind 
the  external  abdominal  ring.  Use,  of  the  internal  oblique  muscle,  to  assist 
the  external  oblique  in  expiration,  and  in  compressing  the  abdominal  viscera, 
also  in  bending  the  trunk  forwards,  or  to  one  side  ; it  can  also  rotate  the  trunk, 
but  in  doing  so,  it  co-operates  with  the  external  oblique  of  the  opposite  side; 
this  muscle  is  covered  by  the  latissimus  dorsi  ; it  lies  on  the  transversalis 
muscle : some  small  vessels  ramify  between  them  ; a small  portion  of  the 
internal  oblique  is  sometimes  superficial,  between  the  external  oblique  and 
latissimus  dorsi,  and  above  the  posterior  part  of  the  ilium.  Along  the  inferior 
border  of  this  muscle  we  observe  the  following: 

Cremaster,  consists  of  a fasciculis  of  pale  fleshy  fibres,  which  arise  from 
the  internal  surface  of  the  external  third  of  Poupart’s  ligament,  and  from  the 
lower  edge  of  the  last  described  muscle;  a few  fibres  also  sometimes  proceed 
from  the  lower  edge  of  the  transversalis  muscle  ; it  frequently  too  has  a tendi- 
nous attachment  to  the  pubis,  behind  the  external  abdominal  ring  ; the  fibres 
all  pass  downwards  and  forwards  around  the  spermatic  cord,  but  chiefly  along 
its  outer  side,  and  are  inserted  into  the  tunica  vaginalis  ; a few  fibres  are  lost 
in  the  scrotum.  Use,  to  support,  compress,  and  raise  the  testicle  and  the 
vessels' ; the  origin  of  this  muscle  is  covered  by  the  tendon  of  the  external 
oblique,  and  lies  on  the  fascia  transversalis  : a small  but  long  nerve,  a branch 
from  one  of  the  lumbar  nerves,  runs  between  its  fibres  ; the  Infer  part  of  the 
muscle  is  superficial  and  very  pale;  in  cases  of  old  hernia,  the  fibres  of  the 
cremaster  are  found  greatly  increased  in  thickness,  and  in  that  form  of  the 
disease  called  the  oblique,  or  common  inguinal  hernia;  this  muscle  alwavs 
forms  one  of  the  coverings  of  the  sac.  The  cremaster  is  absent  in  the  female. 
Raise  off  the  internal  oblique  from  the  transversalis  muscle;  commence  above 
the  anterior  part  of  the  crest  of  the  ilium,  where  the  muscles  are  separated  by 
cellular  membrane,  and  some  branches  of  the  circumflex-ilii  vessels,  make  one 
incision  from  the  ilium  towards  the  cartilage  of  the  9th  rib,  and  another  from 


OR  .MANUAL  OF  ANATOMY. 


?9 

the  ilium,  towards  the  lower  third  of  the  linea  semilunaris;  carefully  dissect 
off  the  posterior  part  of  the  muscle,  towards  the  spine,  and  the  anterior  towards 
the  rectus;  this  portion  can  be  separated  from  the  transversal  is,  a little  beyond 
the  linea  semilunaris. 

Transversalis,  somewhat  square,  broader  anteriorly  than  posteriorly,  arises 
tendinous  from  the  fascia  lumborum  and  the  posterior  part  of  the  crest  of  the 
ilium,  fleshy  from  the  remaining  anterior  part  of  the  crest,  and  from  the  iliac 
third  of  Poupart’s  ligament ; it  also  arises  tendinous  from  the  two  last  ribs, 
and  by  fleshy  slips  from  the  inner  side  of  the  five  succeeding  ; these  indigitate 
with  the  origins  of  the  diaphragm  ; all  the  fibres  pass  transversely  forwards, 
except  the  most  inferior,  which  are  curved  a little  downwards;  they  all  end 
in  a flat  tendon,  which,  near  the  linea  semilunaris,  joins  the  posterior  lamina 
of  the  internal  oblique,  and  is  inserted  along  with  it  into  the  whole  length  of 
the  linea  alba,  into  the  upper  edge  of  the  pubis,  and  into  the  linea  innominata ; 
this  tendon  passes  behind  the  rectus  superiorly;  but  inferior,  that  is,  about 
in'idway  between  the  umbilicus  and  the  pubis  the  conjoined  tendons  pass  an- 
terior to  this  muscle,  and  are  inserted  in  the  manner  before  mentioned.  The 
transversalis  abdominis  is  covered  by  the  internal  and  external  oblique;  it 
lies  on  the  fascia  transversalis  and  the  peritonaeum.  Use,  to  compress  the 
abdominal  viscera,  and  assist  in  expiration;  this  muscle  is  tendinous  before 
and  behind,  fleshy  in  the  middle,  also  above  and  below,  contrary  to  the  two 
oblique  muscles ; the  posterior  tendon  is  described  by  some,  not  improperly, 
as  dividing  into  three  layers  ; the  posterior,  very  strong,  is  continuous  with 
the  fascial  lumborum;  the  middle,  thinner  and  weaker,  is  attached  to  the 
transverse  processes  of  the  lumbar  vertebra,  and  is  separated  from  the  former 
by  the  lumbar  muscles;  and  the  anterior  lamina,  which  is  the  weakest,  is  ex- 
panded over  the  quadratus  lumborum,  and  the  inferior  part  of  the  diaphragm, 
and  is  connected  to  the  sides  of  the  bodies  of  the  lumbar  vertebra.  The 
inferior  edge  of  the  transversalis  is  in  some  degree  confounded  with  that  of 
the  internal  oblique,  particularly  at  their  origin  from  Poupart’s  ligament:  it 
seldom,  however,  descends  as  low  as  that  muscle,  and  it  crosses  the  spermatic 
cord,  or  round  ligament,  just  as  either  of  these  is  about  to  enter  the  abdomen 
Replace  the  oblique  muscles,  divide  their  tendons  all  along  the  side  of  th  ■ 
linea  alba,  and  dissect  them  off  the  rectus  towards  the  linea  semilunaris:  this 
anterior  part  of  the  sheath  adheres  so  closely  to  the  lineae  transversas,  that  it 
is  difficult  to  separate  it  from  them. 

Rectus,  long  and  flat,  broader  above  than  below,  arises  by  a flat  tendon, 
which  is  sometimes  double,  from  the  upper  and  anterior  part  of  the  pubis, 
ascends  parallel  to  its  fellow,  becomes  broad  and  thin  above  the  umbilicus, 
and  is  inserted  into  the  anterior  part  of  the  thorax  by  three  fasciculi,  the 
internal  one  of  which  is  fixed  to  the  ensiform  cartilage  and  costo-xiphoid 
ligament ; the  middle  longer  and  thinner  to  the  cartilage  of  the  sixth  rib ; 
and  the  external  still  broader  and  thinner  to  the  cartilage  of  the  fifth  rib. 
Use,  to  bend  the  chest  towards  the  pelvis,  or  to  raise  the  latter  towards 
the  chest,  also  to  compress  the  abdomen.  The  rectus  is  covered  supe- 
riorly by  the  great  pectoral,  in  the  middle  by  the  tendon  of  the  external, 
and  the  anterior  layer  of  that  of  the  internal  oblique  muscle,  and  inferiorly 
by  the  external  oblique  and  the  conjoined  tendons  of  the  internal  oblique  and 
transversalis,  also  by  the  pyramidalis.  These  muscles  are  much  nearer  to 


80 


THE  DUBLIN  DISSECTOR, 


each  other  below  than  above,  they  are  each  enclosed  in  a distinct  sheath,  which 
consists,  anteriorly,  of  the  tendon  of  the  external  oblique  and  the  anterior 
lamina  of  the  internal  oblique,  posteriorly  of  the  posterior  layer  of  the  in- 
ternal oblique,  and  the  tendon  of  the  transversalis.  This  sheath  commences 
at  the  edge  of  the  thorax,  and  terminates  midway  between  the  umbilicus  and 
the  pubis;  below  which,  all  the  tendons  pass  anterior  to  this  muscle.  If  this 
part  of  the  rectus  be  divided  the  deficiency  in  the  back  of  the  sheath  will  be 
obvious,  as  it  generally  terminates  abruptly  by  a lunated  edge  ; in  some  cases 
however,  it  ends  gradually:  the  epigastric  vessels  ascend  within  this  sheath, 
on  the  posterior  surface  of  the  muscle.  The  sheath  of  the  rectus  serves  to 
confine  this  muscle  in  its  proper  place,  and  to  prevent  it,  when  contracted, 
from  injuring  the  abdominal  viscera  immediately  behind  it;  it  also  strengthens 
the  parietes  of  the  abdomen,  and  prevents  the  more  frequent  occurrence  of 
hernia ; the  deficiency  in  the  back  part  of  the  sheath  below,  may  permit  the 
abdominal  muscles  to  exert  more  direct  influence  on  the  urinary  bladder  when 
distended.  The  rectus  is  intersected  by  three  or  four  irregular,  or  zigzag, 
tendinous  lines ; one  of  these  is  always  to  be  found  opposite  the  umbilicus,  a 
second  midway  between  this  and  the  xiphoid  cartilage,  opposite  to  which  a 
third  is  always  placed  ; if  a fourth  exist,  it  will  be  found  below'  the  umbilicus  ; 
these  intersection  are  not  complete;  they  are  generally  deficient  on  the  back 
part  of  the  muscle  ; the  anterior  part  of  the  sheath  adheres  intimately  to  each 
of  them,  some  fleshy  fibres  pass  over  one  line  and  are  inserted  into  those 
above  and  below;  by  means  of  these  lines  the  rectus  is  enabled  to  act  in  dis- 
tinct or  separate  portions,  so  as  to  compress  different  parts  of  the  abdomen 
in  succesion  : anterior  to  the  origin  of  the  rectus  is  the  following  small  muscle  : 
Pyramidalis,  is  sometimes  absent,  itcwv'ses  broad  and  fleshy  from  the  pubis, 
ascends  obliquely  inwards,  and  is  inserted  narrow'  and  tendinous  into  the 
linea  alba,  midway  between  the  umbilicus  and  pubis.  Use,  it  assists  the 
rectus,  and  makes  tense  the  linea  alba;  it  is  covered  by  the  tendon  of  the 
external  oblique,  by  the  triangular  ligament  and  the  coi%)incd  tendons. 

Dissect  off  the  transversalis  muscle  in  a direction  from  the  ilium  towards 
the  linea  semilunaris,  and  the  fascia  transversalis  will  be  exposed  covering 
the  peritonaeum;  this  fascia  is  connected  to  the  internal  lip  of  the  ilium  and 
to  the  whole  length  of  Poupart’s  ligament,  as  far  as  the  third  insertion,  from 
which  it  is  continued  behind  the  rectus  to  that  of  the  opposite  side ; from 
these  attachments,  the  fascia  transversalis  ascends  between  the  peritonaeum 
and  the  transversalis  muscle,  as  high  as  the  diaphragm  and  as  far  back  as 
the  psoas  magnus ; it  is  very  strong  and  tense  inferiorly  for  about  an  inch 
above  Poupart’s  ligament,  but  superiorly  it  is  little  more  than  condensed  cel- 
lular membrane  : this  fascia  serves  to  support  the  peritonaeum,  particularly 
at  the  inferior  part  of  the  abdomen  where  the  internal  oblique  and  transver- 
salis muscles  are  deficient;  the  spermatic  cord  or  the  round  ligament  always 
perforates  this  fascia  about  three  quarters  of  an  inch  above  Poupart’s  liga- 
ment, and  about  an  inch  and  a half  from  the  pubis ; this  perforation  is  called 
the  internal  abdominal  ring,  and  is  situated  about  midway  between  the  spine 
of  the  ilium  and  the  symphisis  pubis ; it  is  not  a distinct  opening,  for  the 
edges  are  prolonged  along  the  cord,  and  lost  in  its  cellular  covering.  The 
interval  between  the  internal  and  external  abdominal  rings  is  traversed  by 
the  spermatic  cord,  and  is  named  the  inguinal  or  spermatic  canal,  to  the 


OR  MANUAL  OF  ANATOMY. 


81 


anatomy  of  which  the  student  should  particularly  attend,  as  the  disease  of 
inguinal  hernia  is  situated  here,  in  the  treatment  of  which  a correct  know- 
ledge of  this  region  will  be  required.  The  spermatic  or  inguinal  canal  com- 
mences at  the  internal  ring,  and  leads  obliquely  downwards,  forwards,  and 
inwards  to  the  external  ring,  where  it  terminates;  this  passage  is  bounded 
anteriorly  by  the  tendon  of  the  external  oblique  and  by  the  inferior  fleshy 
margin  of  the  internal  oblique  and  transverse  muscles,  posteriorly  by  the  trans- 
versalis  fascia  and  by  the  conjoined  tendons  of  the  two  last  named  muscles, 
interiorly  by  Poupart’s  ligament  and  its  third  insertion,  superiorly  this  space  is 
closed  by  the  apposition  of  its  opposite  sides ; in  the  male  the  spermatic  cord 
and  cremaster  muscle,  and  in  the  female  the  round  ligament  of  the  womb 
passes  through  this  canal,  the  obliquity  or  valve-like  structure  of  which  serves 
to  protect  the  abdomen  against  a protrusion  of  it  contents.  Inguinal  hernia 
occurs  more  frequently  in  the  male  than  in  the  female  sex,  in  consequence 
of  the  spermatic  cord  and  the  inguinal  rings  in  man  being  larger  than  the 
ligamentum  teres  or  these  openings  in  the  female  : -there  are  two  species  of 
this  disease,  oblique  and  direct.  Oblique  inguinal  hernia  is  the  more  com- 
mon form ; in  this  case,  the  peritonaeum  or  the  hernial  sac  with  its  contents, 
protrude  through  the  internal  ring  along  the  anterior  part  of  the  spermatic 
vessels  to  which  it  is  connected  by  the  surrounding  cellular  tissue  and  by  the 
prolongation  of  the  fascia  transversalis  from  the  edges  of  the  opening;  this 
covering  of  the  hernial  sac  is  called  the  fascia  propria  of  inguinal  hernia. 
When  the  tumor  has  arrived  at  the  lower  edge  of  the  transversalis  and  in- 
ternal oblique  it  insinuates  itself  between  the  cremaster  muscle  and  the  ves- 
sels of  the  cord,  along  which  it  descends  to  the  external  ring,  where  it  is  in 
general  delayed  for  some  time;  the  form  of  this  opening  and  the  inter- 
columnar  fascia  preventing  its  free  passage  through  it;  as  the  sac  however 
descends  towards  the  scrotum  these  inter-columnar  fibres  become  closely 
united  to  the  cremaster,  and  are  gradually  elongated  on  the  surface  of  the 
tumor.  If  the  sac  of  an  oblique  inguinal  hernia  which  has  passed  the  external 
ring  be  carefully  dissected,  it  will  be  found  covered  by  the  following  parts; 
beneath  the  integuments  the  superficial  fascia,  in  general  much  thickened  and 
divisible  into  several  laminae,  will  be  seen  to  surround  the  tumor;  on  dis- 
secting off  this,  the  fibres  of  the  cremaster,  in  general  also  thickened,  will  be 
observed  spread  on  the  forepart  and  sides  of  the  sac,  the  inter-columnar  bands 
from  the  external  oblique  tendon  will  be  found  closely  connected  to  this 
muscle,  and  both  will  form  a sort  of  capsule  for  the  sac,  suspending  it  towards 
the  abdomen;  if  this  covering  be  divided,  the  fascia  propria  will  appear 
closely  investing  the  tumor,  and  so  adhering  to  it  as  to  be  separated  with 
difficulty  from  it ; this  covering  can  often  be  divided  into  several  layers,  it 
presents,  however,  great  difference  in  different  cases;  beneath  this,  the  her- 
nial sac,  or  the  peritonaeum  will  be  found,  which  also  in  cases  of  old  hernia 
will  be  considerably  thickened ; on  opening  the  hernial  sac,  its  contents,  either 
omentum  or  intestine  will  be  seen.  The  student  should  next  attend  to  the 
situation  of  the  epigastric  vessels  and  their  relation  to  the  parts  concerned  in 
oblique  inguinal  hernia  ; these  vessels  are  placed  behind  the  fascia  transver- 
salis between  it  and  the  peritonseum,  and  in  general  can  be  discerned  through 
the  fascia;  if  not,  a little  dissection  will  render  them  apparent;  two  veins 
usually  accompany  the  artery,  one  on  either  side ; sometimes  there  is  but  one 
11 


82 


THE  DUBLIN  DISSECTOR, 


epigastric  vein,  and  that  is  on  the  pubal  or  inner  side  of  the  artery ; the  epi- 
gastric artery  arises  from  the  external  iliac  near  Poupart’s  ligament;  it  first 
descends  a little  forwards  and  inwards,  then  ascends  towards  the  rectus 
muscle,  immediately  behind  the  fascia  transversalis,  and  very  near  to  the  in- 
ner or  pubal  side  of  the  internal  abdominal  ring;  in  oblique  inguinal  hernia 
the  neck  of  the  sac  is  nearly  in  contact  with  the  epigastric  vessels,  which  thus 
bound  it  on  its  internal  side,  hence  the  rule  of  practice,  in  performing  the 
operation  for  the  relief  of  strangulated  inguinal  hernia,  when  the  stricture  is 
seated  in  the  neck  of  the  sac,  is,  to  direct  the  edge  of  the  knife  or  bistoury 
upwards  and  outwards.  Direct  or  ventro-inguinal  hei'nia  protrudes  directly 
through  the  external  ring  without  descending  along  the  spermatic  channel : 
the  occurrence  of  this  disease  is  in  a great  degree  guarded  against  by  the 
fascia  transversalis,  and  by  the  conjoined  tendons  which  lie  immediately 
behind  the  external  ring ; the  edge  of  the  rectus,  the  triangular  ligament  and 
the  spermatic  cord  may  be  also  all  enumerated  as  additional  protections  to 
this  part  of  the  abdomen  : in  this  species  of  hernia  the  sac  will  be  found 
covered  only  by  the  integuments,  superficial  fascia  and  some  tendinous  and 
aponeurotic  bands  it  may  have  carried  before  it;  it  is  not  covered  by  the  cre- 
master, and  in  general  it  descends  along  the  inner  side  of  the  cord,  but  in 
some  cases  it  passes  behind  it;  it  is  never,  however,  found  between  the  cre- 
master muscle  and  the  spermatic  vessels.  The  epigastric  vessels  lie  to  the 
iliac  or  outer  side  of  the  neck  of  the  sac;  in  dividing  the  latter  therefore,  in 
case  this  operation  be  required  during  life,  the  edge  of  the  knife  should  be 
directed  upwards  and  inwards.  When  the  disease  of  inguinal  hernia  has 
continued  for  a considerable  length  of  time,  the  spermatic  canal  will  be  found 
altered  in  many  respects  from  its  natural  condition ; it  will  have  become 
dilated  and  shortened,  and  the  abdominal  rings  expanded  and  approximated 
so  as  to  render  it  difficult  to  distinguish  the  oblique  from  the  direct  inguinal 
hernia. 

In  connection  with  inguinal  hernia,  the  student  may  next  study  the  anatomy 
of  the  groin  in  reference  to  crural  hernia , or  he  may  postpone  this  dissection 
until  the  contents  of  the  abdomen  have  been  examined  and  removed ; we  shall 
however  here  subjoin  the  description  of  the  parts  concerned  in  this  disease : 
remove  the  integuments  from  the  anterior  part  of  the  upper  third  of  the  thigh, 
the  superficial  fascia  will  be  seen  descending  over  Poupart's  ligament  to  invest 
the  lower  extremity  ; in  the  groin  this  fascia  is  very  thick,  and  may  be  divided 
into  several  layers,  which  are  separated  by  lymphatic  glands  and  the  superfi- 
cial inguinal  vessels ; this  fascia  may  be  easily  raised  from  the  fascia  lata  on 
the  outer  and  inner  sides  of  the  thigh,  but  in  the  middle  of  the  groin  and 
about  an  inch  below  Poupart’s  ligament,  these  fasciae  are  almost  inseparably 
joined  ; when  the  superficial  fascia  shall  have  been  dissected  off  the  fort,  part 
of  the  thigh,  we  shall  see  several  lymphatic  glands,  the  saphena  vein  and  some 
small  blood-vessels  lying  on  the  fascia ; in  structure  the  latter  more  resembles 
the  superficial,  than  the  fascia  lata  ; the  form  and  boundaries  of  the  inguinal 
region  also  may  then  be  more  distinctly  seen  ; this  space  is  triangular,  the 
base  is  Poupart’s  ligament;  the  apex  is  interiorly,  formed  by  the  meeting  of 
the  Sartorius  and  adductor  muscles ; the  external  side  is  very  prominent,  and 
consists  of  the  sartorius,  iliacus,  rectus  and  other  muscles,  all  covered  by  the 
fascia  lata;  the  internal  or  pubic  side  is  flat  and  on  a plane  posterior  to  the 


OR  MANUAL  OF  ANATOMY. 


83 


iliac  ; it  is  formed  by  the  pectinaeus  and  adductor  muscles,  also  covered  by 
the  fascia  lata.  The  inguinal  lymphatic  glands  are  irregular  in  number  and 
size ; they  are  in  general  about  twelve  in  number,  and  may  be  divided  into  a 
superficial  and  a deep  set  ; the  former  are  the  more  numerous,  and  may  be 
arranged  from  their  situation  into  the  superior  and  inferior ; the  superior  are 
small,  four  or  five  in  number,  lie  parallel  to  Poupart’s  ligament,  some  above, 
others  below  it ; the  inferior  are  two  or  three  in  number,  larger  than  the  former, 
and  placed  perpendicularly  or  parallel  to  the  saphena  vein;  in  general  one 
lies  behind  this  vessel ; the  deep  inguinal  glands  are  beneath  the  fascia  lata, 
are  three  or  four  in  number,  and  are  closely  connected  to  the  sheath  of  the 
femoral  vessels,  chiefly  to  its  inner  side  ; in  general  one  occupies  the  femoral 
ring.  The  Saphena  vein  is  the  principal  cutaneous  vein  of  the  lower  ex- 
tremity; it  will  be  seen  in  a future  dissection  to  arise  from  the  dorsum  and 
inner  side  of  the  foot,  and  to  ascend  in  front  of  the  inner  ankle  along  the  inner 
side  of  the  leg,  and  passing  behind  the  inner  condyle  of  the  femur  it  continues 
to  ascend  along  the  inner  and  anterior  part  of  the  thigh  to  within  about  two 
inches  of  Poupart’s  ligament,  when  it  passes  through  an  opening  in  the  fascia 
lata  (the  saphenic  opening)  and  joins  the  femoral  vein.  The  saphenic  opening 
in  the  fascia  lata  will  be  very  distinctly  seen  if  the  vein  be  divided  on  the 
thigh  and  raised  towards  Poupart’s  ligament,  it  presents  a well  marked  semi- 
lunar edge,  the  concavity  looking  upwards  ; the  edge,  though  apparently 
sharp,  yet  if  carefully  examined  will  be  found  reflected  backwards  on  the 
sheath  of  the  femoral  vessels  ; remove  the  inguinal  glands,  clean  the  surface 
of  the  fascia  lata,  to  the  connections  of  which  in  this  region  the  student  should 
next  attend.  The  fascia  lata  may  be  observed  to  be  united  to  the  spine  of  the 
ilium,  to  the  whole  length  of  Poupart’s  ligament,  also  to  the  linea  innominata 
and  spine  of  the  pubis ; it  covers  the  muscles  on  either  side  of  the  groin,  and 
the  vessels  in  the  middle : for  the  purpose  of  more  particular  examination, 
this  fascia  may  be  divided  into  three  portions,  the  internal  or  pubic  or  pecti- 
neal portion,  the  external  or  iliac,  and  the  middle  or  cribriform  ; the  internal 
or  pubic  portion  covers  the  pectinaeus,  gracilis,  and  adductor  muscles,  and  is 
inserted  internally  into  the  ramus  of  the  ischium  and  pubis;  superiorly  into 
the  linea  innominata  or  ileo-pectinea,  anterior  to  Gimbernuut’s  ligament ; ex- 
ternally it  passes  behind  the  sheath  of  the  femoral  vessels,  and  at  the  edge  of 
the  psoas  tendon  divides  into  two  laminae,  one  passes  beneath  that  tendon, 
and  is  attached  to  the  capsular  ligament  of  the  hip  joint ; the  other  passes  over 
that  tendon  and  is  continued  into  the  deep  surface  of  the  fascia  iliaca.  The 
middle  portion  of  the  fascia  lata  is  very  thin,  and  has  been  termed  the  cribri- 
form fascia  ; this  extends  from  the  saphena  vein  to  Poupart’s  ligament,  and 
is  connected  on  either  side  to  the  pubic  and  iliac  portions  of  the  fascia  lata. 
The  cribriform  fascia  covers  the  femoral  vessels,  and  is  perforated  by  the  lym- 
phatic vessels  passing  to  the  iliac  glands;  this  portion  of  the  fascia  lata  is 
more  closely  connected  than  any  other  to  the  superficial  fascia:  indeed  in 
structure  it  resembles  the  superficial  more  than  the  fascia  lata,  nor  are  its 
fibres  directly  continued  from  those  of  the  fascia  lata;  some  have  therefore 
considered  the  cribriform  fascia  as  a deep  lamina  of  the  superficial  fascia;  in 
many  cases,  however,  it  has  an  aponeurotic  structure  and  appears  to  be  clearly 
derived  from  the  iliac  portion,  and  inserted  into  the  pubic  portion  of  the  fascia 
lata;  it  presents  much  variety  in  this  respect.  The  external  or  iliac portioa 


84 


THE  DUBLIN  DISSECTOR, 


of  the  fascia  lata  is  very  dense  and  strong,  it  is  continued  from  the  external 
surface  of  the  thigh,  and  is  intimately  attached  superiorly  to  the  spine  of  the 
ilium,  and  to  Poupart’s  ligament;  and  uniting  with  the  cribriform  fascia,  is 
continued  in  front  of  the  femoral  vessels,  along  with  the  inferior  fibres  of 
Poupart’s  ligament,  and  is  inserted  along  with  these  into  the  linea  innominata, 
thus  assisting  to  form  the  external  part  or  the  base  of  Gimbernaut’s  ligament. 
If  the  cribriform  fascia  be  removed  along  with  the  superficial  fascia,  then  the 
iliac  portion  of  the  fascia  lata  will  present  the  appearance  of  a crescentic  or 
falciform  process,  extending  across  the  femoral  vessels,  the  concavity  of  which 
process  will  look  downwards  and  inwards : the  inferior  cornu  joins  the  ex- 
ternal cornu  of  the  saphenic  opening,  and  the  superior  cornu  is  inserted  along 
with  the  posterior  fibres  of  Poupart’s  ligament  or  Gimbernaut’s  ligament  into 
the  linea  innominata,  on  the  internal  border  of  the  crural  ring:  although  this 
crescentic  process  appears  to  present  a defined  edge,  yet  if  the  latter  be 
examined  closely  it  will  be  found  reflected  backwards  on  the  sheath  of  the 
vessels  and  on  the  muscles,  in  the  same  manner  as  the  apparent  edge  at  the 
lower  part  of  the  saphenic  opening. 

Next  direct  your  attention  to  the  internal  surface  of  the  crural  arch,  and 
to  the  connection  betiveen  it  and  the  deep  fasciae  of  the  abdomen  ; divide  the 
fascia  transversalis  from  the  spine  of  the  ilium  towards  the  rectus  muscle; 
dissect  it  carefully  down  from  the  peritonaeum,  then  push  up  this  membrane, 
together  with  the  caecum  or  sigmoid  flexure  of  the  colon,  out  of  the  iliac  fossa, 
to  which  they  are  connected  by  very  loose  cellular  membrane;  we  thus  obtain 
a view  of  the  internal  surface  of  Poupart's  ligament,  and  of  the  parts  which 
pass  benealh  it,  and  which  naturally  fill  the  space  or  cavity  of  the  crural  arch: 
first  observe  the  fascia  transversalis  attached  to  the  inner  lip  of  the  ilium  and 
to  Poupart’s  ligament  from  the  spine  of  that  bone,  as  far  as  the  pubis,  into  the 
linea  innominata  of  which  it  is  inserted;  here  also  it  is  inseparably  joined  to 
the  conjoined  tendons  of  the  internal  oblique  and  transverse  muscles  : as  this 
fascia  is  passing  anterior  to  the  iliac  or  femoral  vessels,  a portion  of  it  extends 
beneath  Poupart’s  ligament,  in  front  of  these  vessels,  so  as  to  form  the  ante- 
rior part  of  their  sheath  ; this  process  of  the  fascia  transversalis  soon  becomes 
thin  and  indistinct,  and  is  lost  in  the  cribriform  part  of  the  fascia  lata.  The 
fascia  i/iuca  is  a tolerably  strong  aponeurosis;  it  covers  the  iliac  and  psoas 
muscles,  passes  behind  the  iliac  vessels,  and  adheres  to  the  upper  margin  of 
the  pelvis;  externally  it  is  connected  to  the  inner  edge  of  the  ilium,  and  infe- 
rioriyit  is  attached  to  Poupart’s  ligament,  and  to  the  fascia  transversalis,  front 
the  spine  of  the  ilium  as  far  inwards  as  the  iliac  artery;  here  it  presents  a 
semilunar  edge,  separates  from  Poupart’s  ligament,  and  from  the  fascia  trans- 
versalis, passes  behind  the  femoral  vessels,  forms  the  posterior  part  of  the 
sheath,  adheres  to  the  pubis,  and  to  the  capsule  of  the  hip  joint,  and  is  con- 
nected to  the  pubic  or  pectiiueal  portion  of  the  fascia  lata.  The  fascia  trans- 
versalis and  iliaca  may  be  compared  to  a funnel,  containing  in  the  superior 
wide  portion  the  peritonaeum  and  its  contents,  and  enclosing  in  the  inferior 
narrow  part,  or  pipe,  the  femoral  vessels,  and  one  or  two  lymphatic  glands; 
of  this  funnel  the  fascia  transversalis  forms  the  anterior,  and  the  fascia  iliaca 
the  posterior  wall ; these  fascire  may  be  now  seen  to  be  perfectly  continuous 
with  each  other,  between  the  vessels  and  the  spine  of  the  ilium;  different 
names  only  being  applied  to  d'fferent  portions  of  one  extensive  aponeurosis  ; 


OR  MANUAL  OF  ANATOMY. 


85 


as  the  iliac  and  transverse  fasciae  are  continued  one  into  the  other,  external  to 
the  iliac  artery,  a white  line  may  be  observed ; this  is  the  circumflex  ilii  artery 
enclosed  in  a sort  of  canal  between  these  fasciae  and  Poupart’s  ligament,  to 
which  these  aponeuroses  are  united. 

The  student  should  next  consider  how  the  space,  commonly  called  the 
crural  arch,  is  naturally  filled ; that  portion  of  it  between  the  spine  of  the 
ilium  and  the  iliac  or  femoral  artery  is  occupied  by  the  psoas  and  iliac  mus- 
cles; imbedded  between  these  muscles  is  the  anterior  crural  nerve ; on  the 
pubic  side  of  these  muscles  is  the  femoral  artery,  next  to  which  is  the  femoral 
vein,  and  at  a little  distance  to  the  pubal  side  of  this  vessel  is  Gimbernaut’s 
ligament,  which  closes  the  internal  part  of  this  space;  thus,  almost  all  the 
crural  arch  is  filled,  except  a small  portion  between  the  femoral  vein  and  the 
third  insertion  of  Poupart’s  ligament;  this  space  is  the  femoral  or  crural  ring  ; 
this  is  somewhat  of  a triangular  form,  the  base,  externally,  is  the  femoral  vein, 
the  apex  internally  is  Gimbernaut’s  ligament ; it  is  bounded  anteriorly  by 
Poupart’s  ligament,  and  by  the  superior  fibres  of  the  falciform  process  of  the 
fascia  lata,  and  posteriorly  by  the  pubis,  covered  by  the  pectinasal  muscle, 
and  by  the  pectinasal  portion  of  the  fascia  lata.  Gimbernaut’s  ligament  pre- 
vents femoral  hernia  occurring  internal  to  this  space,  which  is  the  only  part 
in  the  crural  arch  where  a hernia  can  descend,  and  even  here  this  accident  is 
in  a great  degree  guarded  against,  as  a lymphatic  gland  generally  occupies 
this  situation,  and  a layer  of  condensed  cellular  membrane  extends  across  the 
opening;  this  layer  is  named  the  fascia  propria  ; this  fascia,  though  weak  and 
indistinct  in  the  natural  and  healthy  state,  becomes  very  thick  and  strong  in 
cases  of  old  femoral  hernia ; the  fascia  propria  may  be  described  as  arising 
thin  and  delicate  from  the  fascia  iiiaca  on  the  external  side  of  the  iliac  ves- 
sels; passing  over  these  vessels  it  descends  internally  into  the  pelvis;  inte- 
riorly it  is  continued  along  these  vessels  to  Poupart’s  ligament,  covers  the 
femoral  ring,  and  then  ascending  is  lost  on  the  inner  surface  of  the  fascia 
transversalis.  Crural  hernia  cannot  occur  external  to  the  ring,  as  there  the 
femoral  vessels  fill  up  the  space,  and  strong  partitions  pass  from  the  fascia 
transversalis  to  the  fascia  iiiaca  on  the  inner  side  of  the  vein,  and  between  it 
and  the  artery;  these  prevent  the  distension  of  the  sheath  ; the  fascia  propria 
also  rounds  off  the  angle  between  the  fascia  transversalis  and  the  forepart  of 
the  vessels,  and  prevents  a hernia  occurring  in  front  of  the  artery  or  vein ; 
external  to  these  vessels  the  crural  arch  is  completely  closed  by  the  close 
connection  between  the  fasciae  transversalis  and  iiiaca  to  Poupart’s  ligament, 
in  front  of  the  psoas  and  iliac  muscles.  Femoral  hernia  then  can  occur  only 
at  the  femoral  or  crural  ring;  this  disease  is  more  frequent  in  the  female  than 
in  the  male,  the  crural  arch  and  ring  being  larger  in  the  former  than  in  the 
latter;  femoral  hernia  descends  through  a sort  of  canal- which  commences  at 
the  crural  ring,  and  ends  at  the  saphenic  opening  in  the  fascia  lata,  through 
which  the  sac  protrudes;  the  hernial  sac  in  descending  carries  before  it  the 
fascia  propria,  descends  in  the  sheath  of  the  vessels  along  the  inner  side  of 
the  vein,  and  may  remain  in  this  situation  for  a considerable  time;  as  the 
tumor  increases  in  size  it  bursts  through  the  sheath,  and  either  tears  or  dilates 
some  opening  in  the  cribriform  fascia,  and  then  turns  forwards  into  the  groin  ; 
if  the  tumor  increase  still  further,  it  is  found  to  turn  upwards  over  Poupart’s 
ligament,  and  to  rest  on  the  lower  part  of  the  tendon  of  the  external  oblique ; 


86 


THE  DUBLIN  DISSECTOK, 


the  form  of  the  crural  ring,  the  course  of  the  superficial  epigastric  vessels, 
and  the  close  connection  between  the  superficial  and  cribriform  fasciae,  account 
for  its  ascending  in  this  manner.  If  we  dissect  off  the  integuments  from  a 
femoral  hernia  of  long  standing,  we  shall  find  beneath  them  the  superficial 
fascia  so  increased  in  thickness  and  vascularity  as  to  present  a compact  and 
almost  fleshy-like  appearance;  when  this  shall  have  been  divided,  the  tumor 
can  be  brought  down  off  the  abdomen  into  the  groin,  and  will  be  found  covered 
by  a dense  and  smooth  capsule,  which  often  presents  a glossy  appearance ; 
this  is  the  fascia  propria;  in  dissecting  off  this,  it  will  in  general  be  found  to 
consist  of  several  laminse,  which  sometimes  separate  so  easily  and  appear  so 
distinct  as  to  lead  an  inexperienced  operator  to  suppose  that  the  hernial  sac 
itself  is  exposed.  These  then  are  the  coverings  of  the  sac,  which  is  thus 
placed  external  or  superficial  to  the  fascia  lata:  the  neck  of  the  sac,  however, 
it  is  to  be  recollected,  lies  deep  within  the  sheath  of  the  vessels,  and  is  there- 
fore covered  by  the  fascia  transversalis,  and  by  the  superior  cornu  of  the  fal- 
ciform process  of  the  fascia  lata.  Let  the  student  now  review  the  dissection 
that  has  been  made;  let  him  move  die  thigh  in  different  directions,  and  he 
will  remark  that,  when  it  is  rotated  inwards,  Poupart’s  and  Gimbernaut’s 
ligaments,  as  well  as  the  fascia  lata,  feel  relaxed,  and  that  the  crural  ring  will 
feel  larger  or  more  dilatable;,  let  him  also  observe  the  relation  of  the  femoral 
vein,  the  epigastric  vessels,  and  the  spermatic  cord  or  round  ligament  to  this 
opening;  pass  up  the  finger  from  the  groin  into  the  crural  ring,  and  suppose 
that  the  stricture  on  femoral  hernia  was  seated  here,  and  that  this  opening 
required  to  be  dilated,  he  will  now  perceive  that  this  may  be  done  with  most 
safety  by  directing  the  edge  of  the  bistoury  forwards  and  a little  inwards,  so 
as  to  divide  the  external  edge  of  Gimbernaut’s  ligament,  which  edge  is  com- 
posed  of  the  insertion  of  the  superior  cornu  of  the  falciform  process  of  the 
fascia  lata;  the  stricture  on  femoral  hernia  may,  however,  be  seated  lower 
down  than  in  the  neck  of  the  sac  ; it  may  be  situated  in  that  opening  of  the 
cribriform  fascia  through  which  the  hernial  sac  has  protruded  ; in  such  a case, 
the  stricture  may  be  divided  by  directing  the  edge  of  the  knife  directly  in- 
wards along  the  surface  of  the  Pectimeus  muscle. 

§ 2. — Dissection  of  the  Viscera  of  the  Abdomen. 

The  abdomen  is  the  largest  cavity  in  the  body;  it  is  of  an  oval  form  ; its 
capacity,  and  in  some  degree  its  figure,  differ  at  different  ages  and  in  difl’erent 
subjects  ; it  is  bounded  superiorly  by  the  diaphragm,  anteriorly  and  laterally 
by  the  abdominal  muscles,  interiorly  by  the  true  and  false  pelvis,  and  poste- 
riorly by  the  lumbar  vertebrae,  the  crura  of  the  diaphragm,  and  the  psoas  and 
quadrati  lumborum  muscles.  Although  the  expression  “ cavity  of  the  ab- 
domen” is  in  common  use,  it  is  not  correct,  for  during  life  there  is  no  cavity, 
as  the  diaphragm  and  abdominal  muscles  by  their  alternate  action  keep  up 
such  a constant  and  uniform  pressure  on  the  viscera,  that  these  and  the  pa- 
rietes  are  always  in  perfect  contact.  The  abdomen  contains  the  peritonaeum 
and  the  organs  of  digestion;  the  kidneys,  renal  capsules  and  ureters;  also 
the  thoracic  duct,  the  aorta,  vena  cava,  and  the  numerous  branches  of  these 
vessels.  The  abdomen  is  very  generally  divided  by  anatomical  writers  into 
nine,  and  by  some  into  twelve  different  regions  ; by  drawing  two  transverse 


OR  MANUAL  OF  ANATOMY. 


87 


lines,  one  between  the  extremities  of  the  cartilages  of  the  9th  rib,  and  the 
other  between  the  anterior  superior  spinous  processes  of  the  ossailii,  we  may 
define  three  regions  ; the  epigastric  above,  the  umbilical  in  the  middle,  and 
the  hypogastric  below  ; and  then  by  drawing  a vertical  line  on  each  side  from 
the  extremity  of  the  ninth  rib  to  the  anterior  superior  spinous  process  of  the 
ilium,  we  shall  subdivide  each  of  these  regions  into  three  parts : the  three 
* divisions  of  the  epigastric  region  are  the  epigastrium,  or  scrobiculus  cordis 
in  the  centre,  and  the  right  and  left  hypochondriac  regions  on  either  side  ; the 
epigastrium  is  immediately  below  the  ensiform  cartilage,  and  the  hypochon- 
driac regions  are  covered  by  the  false  ribs;  the  lateral  portions  of  the  um- 
bilical division  are  the  lumbar  regions ; the  middle  of  the  hypogastric  region 
is  the  hypogastrium,  and  the  lateral  portions  are  the  iliac  regions  ; the  lower 
part  of  the  hypogastrium  is  called  by  some  the  pubic  region,  and  the  lower 
part  of  each  iliac  division  is  called  inguinal  region,  and  contains  the  iliac 
vessels,  and  in  the  male  the  spermatic  cord,  and  in  the  female  the  round  liga- 
ment of  the  uterus.  The  viscera,  which  constantly  or  occasionally  occupy 
the  other  regions  of  the  abdomen  will  be  seen  when  the  peritonaeal  cavity  has 
been  opened,  and  with  these  the  student  should  make  himself  familiar,  as  this 
knowledge  may  be  of  practical  importance  in  cases  of  wounds  penetrating 
this  cavity,  or  in  making  an  examination  during  life  to  detect  any  suspected 
organic  disease.  Dissect  the  abdominal  muscles  off  the  peritonaeum ; these 
can  be  easily  separated  laterally  and  inferiorly;  but  anteriorly,  particularly 
near  the  umbilicus,  it  will  be  found  very  difficult  to  detach  the  sheath  of  the 
rectus  from  this  membrane ; the  external  surface  of  the  peritonaeum,  which 
is  thus  exposed,  appears  rough  and  cellular,  from  its  connection  to  the  super- 
incumbent muscles;  three  ligamentous  cords  are  seen  extending  along  it 
anteriorly  and  inferiorly,  from  the  summit  and  sides  of  the  urinary  bladder 
towards  the  umbilicus ; the  central  one  of  these  is  the  remains  of  the  urachus, 
and  that  on  each  side  is  the  obliterated  umbilical  or  hypogastric  artery  ; an- 
teriorly and  superiorly  we  perceive  another  ligamentous  substance,  ascending 
from  the  umbilicus  obliquely  backwards,  and  to  the  right  side ; this  is  the 
remains  of  the  umbilical  vein ; it  is  at  first  placed  between  the  peritonaeum 
and  the  muscles,  but  it  soon  sinks  deep  towards  the  liver,  carrying  around  it 
a fold  of  peritonaeum,  named  the  suspensory  ligament  of  the  liver,  which 
will  be  seen  when  the  peritonaeum  is  opened;  the  epigastric  vessels  also  may 
be  observed  ascending  from  each  inguinal  region,  and  branches  of  the  internal 
mammary  arteries  descending  on  the  surface  of  this  membrane.  Next  open 
the  peritonaeum  by  an  incision  from  the  ensiform  cartilage  to  the  umbilicus, 
and  from  this  point  carry  another  on  each  side  obliquely  downwards,  to  the 
spine  of  the  ilium : on  throwing  down  the  inferior  flap  thus  formed,  we  remark 
on  its  internal  surface  the  projections  of  the  three  ligamentous  cords  which 
were  before  noticed  as  ascending  from  the  bladder  to  the  umbilicus ; we  may 
also  remark  how  the  external  of  these  cords,  or  the  obliterated  umbilical 
artery  on  each  side,  throws  the  lower  part  of  the  peritonaeum  into  pouches, 
two  on  each  side,  the  external  and  internal  inguinal  pouches ; the  former 
lies  between  the  ilium  and  the  obliterated  hypogastric  vessel,  the  latter  between 
this  cord  and  the  fundus  of  the  bladder.  The  external  pouch  is  large  and 
very  concave  internally,  and  appears  to  protrude  towards  the  inguinal  canal : 
the  existence  of  this  pouch  may  conduce  to  the  production  of  oblique  inguinal 
as  well  as  of  femoral  hernia;  the  internal  pouch  lies  behind  the  external  ring. 


88 


THE  DUBLIN  DISSECTOR, 


and  becomes  protruded  in  direct  or  ventro- inguinal  hernia.  When  the  peri- 
tonaeum has  been  fully  opened,  we  perceive  its  inner  surface  smooth  and 
polished  like  all  serous  membranes,  and  filling  its  cavity  we  see  the  numerous 
digestive  organs  ; these,  though  apparently  within  this  bag,  are  really  behind 
it,  and  only  protrude  the  posterior  side  of  this  large  sac  into  the  cavity ; 
nothing  is  contained  within  the  peritonaeum  but  the  serous  fluid,  which  is 
constantly  exhaled,  for  the  purpose  of  lubricating  its  opposite  sides.  We 
also  obtain  a partial  view  of  the  following  organs,  which  in  general  occupy 
the  same  situation  during  life  as  we  perceive  them  now  to  hold.  Filling  the 
right  hypochondrium  is  the  liver,  with  the  fundus  of  the  gall  bladder  pro- 
jecting a little  below  it.  In  the  epigastric  region  wre  see  a portion  of  the 
liver  also,  resting  on  the  stomach,  and  below  it  we  see  the  pylorus  and  the 
commencement  of  the  duodenum;  in  the  left  hypochondrium  lie  the  spleen 
and  great  extremity  of  the  stomach  ; in  the  right  and  left  lumbar  regions  we 
find  the  colon,  ascending  through  the  former,  and  descending  through  the 
latter,  behind  which  is  each  kidney;  the  duodenum  also  partly  occupies  the 
right  lumbar  region  ; through  the  proper  umbilical  region  the  transverse  colon 
runs,  not  fixed  however  in  any  particular  part  of  it,  and  from  this  intestine 
we  perceive  the  great  omentum  descending  towards  the  lower  part  of  the 
abdomen,  presenting  however,  very  different  appearances  in  different  sub- 
jects; in  some  being  expanded  over  the  small  intestines,  so  as  nearlv  to 
conceal  them  ; in  others  being  coiled  up  into  a narrow'  fold,  and  often  con- 
cealed in  some  recess  between  the  surrounding  viscera  : the  convolutions  of 
the  jejunum  and  ilium  intestines  occupy  the  lower  part  of  the  umbilical,  and 
extend  indifferently  into  the  hypogastric,  and  iliac  regions;  the  caecum  or 
caput  coli  is  fixed  in  the  right,  and  the  sigmoid  flexure  of  the  colon  in  the 
left  iliac  fossa;  the  rectum  and  other  pelvic  viscera  occupy  the  hypogastric 
regions,  but  will  of  course  change  their  own  situation  as  well  as  that  of  the 
small  intestines,  according  as  they  are  contracted  or  distended.  The  studen* 
may  next  examine  the  anatomy  of  the  peritonaeum  ; this  is  the  largest  serous 
sac  or  membrane  in  the  body;  it  lines  the  abdominal  muscles,  and  covers 
almost  all  the  abdominal  viscera;  that  portion  which  adheres  to  the  parietes 
is  called  the  parietal , and  that  covering  the  viscera  the  visceral  layer. 

The  peritonaeum  is  a shut  sac,  and  therefore  when  opened  presents  one  con- 
tinued surface,  which  may  be  traced  throughout  the  whole  extent  without 
any  interruption  ; it  covers  the  viscera  in  such  a manner  as  that  they  lie  ex- 
ternal or  posterior  to  it ; the  familiar  example  of  the  double  night-cap  on  the 
head  has  been,  not  unaptly,  adduced,  to  explain  how  the  viscera  may  be 
covered  by  the  peritonaeum,  and  yet  really  lie  beneath  it  or  behind  it.  Let 
us  now  trace  this  membrane  through  its  entire  extent,  commencing  at  the 
umbilicus  ; from  the  transverse  incision  that  wras  made  into  it  in  this  situation, 
we  may  perceive  it  to  ascend  on  the  internal  surface  of  the  transverse  and 
recti  muscles,  as  high  as  the  margin  of  the  thorax ; then  bending  back,  it 
adheres  to  the  inferior  surface  of  the  diaphragm,  and  continues  very  far  back 
on  this  muscle,  particularly  in  the  left  hypochondrium  ; from  the  diaphragm 
it  is  reflected  on  the  spleen  on  the  left  side,  on  the  stomach  in  the  centre,  and 
on  the  liver  on  the  right  side  ; it  is  also  reflected  on  this  last  named  viscus  by 
a distinct  fold,  the  falciform  or  suspensory  ligament,  from  the  umbilicus,  and 
from  the  abdominal  muscles  on  the  right  side  of  the  linea  alba  : as  the  perito 
naeum  is  reflected  from  the  diaphragm  on  each  side  of  these  organs  in  the 


OR  MANUAL  OF  ANATOMY. 


89 


epigastric  and  hypochondriac  regions,  it  forms  folds,  which  to  a certain  extent 
serve  as  ligaments ; these  will  be  noticed  more  particularly  in  the  examina- 
tion of  the  individual  viscera.  Having  covered  the  organs  in  the  upper 
division  of  the  abdomen,  it  is  continued  downwards  in  the  following  manner : 
having  invested  both  surfaces  of  the  liver  as  far  as  its  transverse  fissure;  it 
is  connected  along  and  around  the  vessels  of  this  gland  towards  the  lesser 
curvature  of  the  stomach;  this  fold,  which  thus  surrounds  the  hepatic  vessels, 
is  called  the  lesser  or  the  gastro-hepatic  omentum  ; it  is  also  sometimes  named 
the  capsule  of  Glisson;  at  the  lesser  arch  of  the  stomach  the  two  laminae  of 
this  process  separate  to  enclose  the  stomach,  the  posterior  layer  giving  a serous 
covering  to  the  back  part  of  this  organ  and  in  like  manner  the  anterior  layer 
covering  its  anterior  surface,  on  which  it  is  continuous  with  that  portion  of 
peritonaeum  which  has  descended  from  the  diaphragm,  and  with  that  which  is 
also  continued  from  the  spleen  to  the  stomach.  The  peritonaeum  having  thus 
enclosed  the  stomach  and  its  vessels  between  the  two  layers  of  the  lessor 
omentum,  we  next  observe  that  these  laminae  having  passed  the  great  curva- 
ture of  the  stomach  touch  each  other,  and  being  joined  by  the  peritonaeum 
from  the  lower  end  of  the  spleen,  descends  under  the  name  of  the  gastro- 
colic or  the  great  omentum,  to  the  lower  part  of  the  abdomen  : in  general  it 
descends  lower  on  the  left  side  than  on  the  right;  it  then  turns  on  itself,  and 
ascends  obliquely  backwards  to  the  arch  of  the  colon,  along  the  convex  edge 
of  which  its  laminae  separate  to  enclose  this  intestine  and  its  vessels  ; along 
the  concave  edge  of  the  colon  these  laminae  again  unite,  and  increasing  in 
density  form  that  process  which  is  called  the  transverse  meso-colon,  which 
passes  backwards  to  the  spine:  opposite  the  duodenpm  this  process  separates 
into  an  ascending  and  descending  layer : the  inferior  division  of  the  duodenum 
lies  between  these ; the  ascending  layer  proceeds  in  front  of  the  lower  and 
middle  divisions  of  the  duodenum,  up  to  the  back  part  of  the  right  lobe  of  the 
liver,  where  it  becomes  continuous  with  the  peritonaeal  tunic  of  that  viscus 
and  with  the  posterior  layer  of  the  lessor  omentum  which  is  descending  along 
the  back  part  of  the  hepatic  vessels.  The  descending  layer  of  the  transverse 
meso-colon  expands  into  each  lumbar  region,  in  which  it  attaches  the  lumbar 
portions  of  the  colon  by  a duplicature  called  the  right  and  left  lumbar  meso- 
colon ; in  the  centre  the  inferior  layer  of  the  transverse  meso-colon  adheres 
to  the  vertebral  column,  and  to  the  great  vessels  which  lie  upon  it,  and  is 
thence  reflected  forwards  and  downwards  over  the  small  intestines  and  their 
vessels,  and  returns  around  these  to  the  spine,  thus  forming  a very  important 
and  remarkably  folded  or  plaited  process  named  the  mesentery.  From  the  . 
inferior  surface  of  the  mesentery  the  peritonaeum  extends  into  either  iliac 
region,  and  descends  into  the  pelvis  in  the  middle ; it  serves  to  connect  the 
caecum  in  the  right,  and  the  sigmoid  curve  of  the  colon  in  the  left  iliac  fossa; 
in  the  pelvis  the  peritonaeum  descends  around  the  rectum,  forming  the  process 
named  the  meso-rectum ; opposite  the  lower  third  of  the  sacrum,  it  is  reflected 
to  the  lower  and  back  part  of  the  bladder,  and  in  the  female  to  the  upper  and 
back  part  of  the  vagina,  from  which  it  ascends  on  the  uterus,  and  forms  on 
each  side  of  this  organ  the  broad  ligament  which  supports  the  Fallopian  tube 
and  the  ovary  : the  peritonaeum  is  then  reflected  from  the  fore-part  of  the 
uterus  to  the  back  of  the  bladder,  ascends,  both  in  the  male  and  female,  along 
the  posterior  surface  and  sides  of  this  viscus  to  its  superior  fundus,  from  which 
12 


90 


THE  DUBLIN  DISSECTOR, 


and  from  the  iliac  fossae,  it  is  continued  to  the  abdominal  mucles ; forms  the 
inguinal  pouches,  and  may  then  be  traced  on  the  inner  surface  of  the  recti 
and  transverse  muscles  up  to  the  umbilicus,  where  the  sac  was  opened.  The 
different  folds  which  the  peritonaeum  forms  in  this  course  are  termed  processes, 
the  principal  of  which,  in  addition  to  the  ligaments  of  the  severaL  organs, 
which  shall  be  noticed  in  the  description  of  the  latter,  are,  the  lesser  omentum, 
the  great  omentum,  the  splenic  omentum,  the  colic  omentum,  the  appendices 
epiploicse,  the  transverse,  and  the  right  and  left  lumbar  meso-colons,  the 
mesentery,  meso-caecum,  and  meso-rectum. 

The  lesser  or  gastro -hepatic  omentum  consists  of  two  laminae,  which  extend 
from  the  transverse  fissure  of  the  liver  to  the  lesser  curvature  of  the  stomach 
and  to  the  upper  part  of  the  duodenum  : it  contains  between  its  layers  the  ves- 
sels of  the  liver,  viz.  the  hepatic  artery  to  the  left  side,  the  ductus  choledochus 
to  the  right,  and  the  vena  porta  behind  and  between  both  ; at  its  connection 
to  the  stomach,  it  encloses  the  coronary  vessels  of  this  organ ; the  lesser 
omentum  lies  anterior  to  the  foramen  of  Winslow,  this  omentum  seldom  con- 
tains much  fat. 

The  great  or  gastro-colic  omentum  also  consists  of  two  laminae,  which  de- 
scend from  the  lower  end  of  the  spleen,  and  from  the  anterior  and  posterior 
surface  of  the  stomach  ; between  these  laminae  are  several  long  and  tortuous 
vessels,  descending  from  the  vessels  of  the  stomach,  and  some  adipose  sub- 
stance the  quantity  of  which  varies  very  much  in  different  subjects;  the  great 
omentum  descends  in  front  of  the  large  and  small  intestines  to  the  lower  part  of 
the  abdomen,  in  general  lower  on  the  left  than  on  the  right  side  ; (this  explains 
the  reason  why  omentum  is  more  frequently  found  in  a herniary  sac  on  the 
left  than  on  the  right  side;)  it  then  turns  upwards  and  backwards  until  it 
reaches  the  transverse  arch  of  the  colon  ; that  portion  of  omentum,  therefore, 
which  is  inferior  to  the  colon,  consists  of  four  laminae,  two  descending  and 
two  ascending;  these,  in  the  young  subject,  can  be  separated  from  each  other, 
and  a distinct  cavity  can  be  seen  between  them  ; this  is  part  of  the  cavitv  or 
bag  of  the  omentum  which  communicates  with  the  general  cavity  of  the  peri- 
tonaeum by  the  opening  of  Winslow,  and  which  will  be  more  particularly  de- 
scribed presently;  at  the  arch  of  the  colon  the  two  ascending  laminae  of  the 
great  omentum  separate  to  enclose  this  intestine,  and  again  uniting  form  the 
commencement  of  the  following  process. 

The  transverse  meso-colon  extends  from  the  concave  border  of  the  arch  of 
the  colon  backwards  to  the  spine ; this  process  is  very  strong  and  dense,  it 
encloses  the  vessels  of  the  colon  and  forms  a sort  of  division  or  partition  in 
the  abdomen  between  the  epigastric  and  umbilical  regions ; when  the  transverse 
meso-colon  has  arrived  at  the  spine,  its  two  laminae  separate,  one  descends, 
the  other  ascends;  the  descending  layer  is  very  strong,  expands  laterally  into 
the  right  and  left  lumbar  regions,  in  each  of  which  it  is  reflected  either  par- 
tially or  perfectly  around  the  ascending  and  descending  colon,  and  thus  forms 
a short  fold  or  process  very  irregular  in  different  subjects,  termed  the  right 
and  left  lumbar  meso-colons ; the  inferior  or  descending  layer  of  the  trans- 
verse meso-colon  is  continued  obliquely  downwards  in  the  middle  line  to  form 
the  mesentery,  a process  which  we  shall  trace  when  we  have  pursued  the 
superior  or  ascending  layer  of  the  meso-colon  to  its  termination.  This  lamina 
is  thin  and  delicate;  it  ascends  in  front  of  the  inferior  and  middle  portions  of 


ORt  MANUAL  OF  ANATOM*. 


91 


the  duodenum,  and  of  the  pancreas ; it  also  covers  the  aorta  and  vena  cava, 
and  continues  along  this  latter  vessel  to  the  liver,  on  the  spigelian  lobe  of  which 
it  expands,  and  on  it  and  on  the  right  lobe,  behind  the  foramen  of  Winslow, 
it  becomes  continuous  with  the  peritonaeum,  which  has  been  reflected  on  the 
back  part  of  the  liver  from  the  diaphragm.  As  this  ascending  layer  proceeds 
in  front  of  the  pancreas,  it  is  continuous  on  each  side  with  the  posterior  layer 
of  the  lesser  omentum  which  covers  the  back  part  of  the  stomach.  This  as- 
cending layer  may  be  best  seen  and  traced  by  dividing  the  great  omentum  a 
little  below  the  stomach,  and  raising  this  organ  towards  the  thorax:  we  shall 
thus  lay  open  the  cavity  of  the  omentum,  and  shall  be  able  to  trace  theparietes 
of  this  bag  through  their  whole  extent. 

The  cavity  of  the  omentum  extends  from  the  transverse  fissure  of  the  liver 
superiorly,  to  the  lower  border  of  the  great  omentum  inferiorly ; it  is  bounded 
anteriorly  by  the  lesser  omentum,  the  stomach,  and  the  anterior  or  descend- 
ing portion  of  the  great  omentum ; inferiorly  it  is  formed  by  the  great  omentum 
turning  on  itself;  and  posteriorly  it  is  bounded  by  the  ascending  portion  of 
the  great  omentum,  by  the  colon,  by  the  transverse  meso-colon,  and  by  the 
superior  or  ascending  layer  of  this  process,  which  terminates  at  the  liver.  The 
cavity  of  the  omentum  communicates  with  the  general  peritonaeal  cavity  through 
the  foramen  of  Winslow;  this  opening  is  situated  in  the  lower  part  of  the  right 
hypochondriac  region  just  above  the  right  lumbar;  it  is  somewhat  oval,  bounded 
anteriorly  by  the  lesser  omentum  and  by  the  hepatic  vessels,  posteriorly  by 
the  termination  of  the  ascending  layer  of  the  meso-colon  which  invests  the 
vena  cava,  superiorly  by  the  lobulus  caudatus  of  the  liver,  and  inferiorly  by 
the  superior  portion  of  the  duodenum  ; if  the  membrane  composing  the  omenta 
be  perfect,  and  if  air  be  forced  through  this  opening,  it  will  descend  behind 
the  stomach,  and  will  inflate  the  omental  cavity  ; the  great  omentum,  however, 
in  general  is  so  cribriform  that  this  experiment  cannot  be  performed ; the 
principal  use  of  this  cavity  is  most  probably  to  afford  a serous  surface  or  cavity 
l'or  the  stomach  to  move  or  to  distend  into  posteriorly  during  the  process  of 
digestion. 

The  splenic  omentum  extends  from  the  fissure  in  the  spleen  to  the  great  end 
of  the  stomach,  and  is  continuous  inferiorly  with  the  great  omentum;  the 
splenic  vessels  and  the  vasa  brevia  are  contained  between  the  laminae  of  this 
process. 

The  colic  omentum  is  a fold  of  peritonaeum  which  descends  from  the  upper 
part  of  the  right  or  ascending  colon  ; it  generally  lies  posterior  to  the  great 
omentum  ; it  is  composed  of  two  laminae,  between  which  are  contained  blood- 
vessels and  adipose  substance. 

The  appendices  epiploicse  are  attached  all  along  the  large  intestine ; but 
principally  to  the  transverse  arch  of  the  colon ; they  are  small  prolongations 
of  the  peritonaeum,  filled  with  a soft  fatty  substance;  they  are  never  found 
attached  to  the  small  intestine;  they  vary  very  much  in  different  subjects  in 
number  and  size ; their  use  is  not  ascertained. 

The  mesentery  is  the  largest  and  most  remarkably  process  of  the  peritonaeum; 
it  is  continuous  with  the  descending  layer  of  the  meso-colon,  and  extends 
from  the  left  side  of  the  second  lumbar  vertebra  obliquely  downwards  to  the 
right  iliac  fossa ; this  is  the  root  of  the  mesentery ; from  this  it  expands  very 
much,  and  is  folded  round  the  jejunum  and  ileum  intestines,  and  then  returns 


92 


THE  DUBLIN  DISSECTOR, 


again  to  the  spine  or  to  the  inferior  surface  of  the  root;  the  laminae  of  the 
mesentery  can  be  easily  separated ; between  them  we  find  the  mesenteric  arte- 
ries, veins  and  nerves,  also  numerous  absorbent  vessels  and  glands ; the  mes- 
entery serves  to  support  the  convolutions  of  the  small  intestines  and  the 
numerous  vessels  passing  to  and  from  these. 

The  meso-caecum  is  a fold  of  peritonaeum  which  attaches  the  caecum  to  the 
right  iliac  fossa;  this  process,  however,  is  frequently  imperfect ; the  posterior 
portion  of  this  intestine  being  sometimes  deprived  of  a serous  coat,  and  con- 
nected to  the  iliac  muscle  by  cellular  membrane. 

The  meso-rectum  is  a short  fold  of  peritonaeum  which  connects  the  superior 
portion  of  the  rectum  to  the  upper  and  anterior  part  of  the  sacrum ; it  encloses 
the  haemorrhoidal  vessels  and  nerves. 

The  viscera  of  the  abdomen  are  the  digestive  and  urinary  organs;  the 
former  we  shall  examine  first;  they  may  be  divided  into  the  membranous  and 
glandular.  The  membranous  viscera  are  the  stomach  and  intestinal  tube; 
the  latter  is  divided  into  the  small  and  large  intestine  ; the  small  intestine  is 
subdivided  into  the  duodenum,  jejunum,  and  ileum;  the  large  intestine  into 
the  caecum,  colon,  and  rectum.  The  glandular  viscera  are  the  liver,  spleen, 
and  pancreas.  We  shall  consider  the  membranous  viscera  first,  and  com- 
mence with  the  description  of  the  stomach,  which  is  the  most  important  part 
of  the  digestive  apparatus,  the  principal  change  in  the  food  being  accomplished 
in  this  organ. 

The  stomach  is  placed  between  the  oesophagus  and  duodenum,  and  com- 
municates with  both;  it  is  situated  in  the  left  hypochondriac  and  epigastric 
regions,  and  a small  portion  of  it  extends  into  the  right  hypochondrium  : from 
the  left  side  it  passes  across  the  epigastric  region,  obliquely  downwards  and 
forwards,  and  near  its  right  or  pyloric  extremity  it  bends  a little  upwards  and 
backwards.  The  stomach  is  connected  to  the  diaphragm  by  the  oesophagus 
and  by  the  peritonaeum ; to  the  spleen  by  the  splenic  omentum  ; to  the  liver 
by  the  lesser  omentum,  and  to  the  arch  of  the  colon  by  the  great  omentum. 
If  the  stomach  be  moderately  distended  with  air  or  fluid,  its  form  and  con- 
nections can  be  better  understood  ; it  will  then  appear  somewhat  of  a conical 
figure,  the  base  to  the  left  side,  the  apex  to  the  right,  the  intermediate  part 
being  somewhat  curved  ; it  will  present  two  extremities,  the  left  and  right; 
two  orifices,  the  cardiac  and  pyloric  ; two  surfaces,  an  anterior  or  superior,  a 
posterior  or  inferior;  and  two  curvatures  or  edges,  the  lesser  or  concave,  the 
greater  or  convex.  The  left  or  splenic  extremity  is  very  large,  swells  into  the 
left  hypochondrium  beneath  the  ribs,  so  as  nearly  to  conceal  the. spleen;  the 
right  or  pyloric  extremity  is  much  smaller,  is  cylindrical  and  slightly  convo- 
luted like  an  intestine;  it  lies  anterior  and  inferior  to  the  left  or  splenic  end, 
and  extends  to  the  fundus  of  the  gall  bladder  or  to  the  edge  of  the  lohulus 
quadratus  of  the  liver;  it  sometimes  descends  into  the  umbilical  region.  The 
cardiac  orifice  is  the  highest  point  of  the  stomach  ? it  is  situated  between  the 
left  or  great  end  and  the  lesser  curvature,  about  three  inches  distant  from  the 
former  ; it  is  surrounded  by  vessels  and  nerves.  The  pyloric  orifice  is 
between  the  stomach  and  the  duodenum  ; it  lies  to  the  right  side  of  the  spine  ; 
it  is,  in  general,  in  contact  with  the  liver  and  gall  bladder,  and  anterior  to  the 
pancreas  ; it  lies  inferior,  anterior,  and  to  the  right  side  of  the  cardiac  orifice  : 
it  has  a peculiar  firm,  hard  feel.  The  anterior  surface  looks  upwards  and 


OR  MANUAL  OF  ANATOMY. 


93 


forwards,  and  is  in  contact  with  the  diaphragm,  the  ribs,  and  the  left  lobe  of 
the  liver.  The  posterior  surface  looks  backwards  and  downwards,  and  rests 
on  the  meso-colon.  The  lesser,  or  concave  edge  of  the  stomach,  looks  back- 
wards and  upwards  towards  the  spine  and  lobulus  spigelii  of  the  liver;  this 
edge,  near  the  pylorus,  is  convex!,  the  great  edge  being  concave  opposite  to 
this  ; the  lesser  omentum  is  attached  to  it,  and  the  coronary  vessels  run  along 
it.  The  great  or  convex  edge  looks  forwards  and  downwards  towards  the 
colon  ; to  it  the  great  omentum  and  the  epiploic  vessels  are  attached ; in  the 
empty  or  contracted  state  of  the  stomach,  these  edges  are  thin  and  directed 
almost  vertically,  but  when  the  stomach  is  distended,  they  become  enlarged 
and  round,  and  continuous  with  the  surfaces.  The  stomach  is  composed  of 
three  tunics,  a serous,  a muscular,  and  a mucous;  these  are  connected  to 
each  other  by  two  laminae  of  cellular  membrane  ; the  serous  or  peritonseal coat 
is  derived,  as  was  before  explained,  from  the  laminae  of  the  lesser  omentum, 
separating  at  the  lesser  curvature,  expanding  over  its  surfaces,  and  uniting 
along  the  convex  edge,  to  form  the  great  omentum:  the  serous  coat  is  loosely 
united  to  the  edges,  but  almost  inseparably  so  to  the  middle  of  each  surface 
and  to  the  pyloric  extremity ; a layer  of  very  fine  cellular  tissue  connects  this 
to  the  following  tunic,  the  muscular ; this  consists  of  fibres,  which  run  in 
three  different  directions;  the  first  or  superficial  are  longitudinal;  they  are 
continued  from  the  oesophagus,  and  are  very  strong  along  the  curvatures,  par- 
ticularly on  the  lesser;  the  middle  layer  of  fibres  run  circularly;  they  com- 
mence at  the  left  extremity,  orcul  de  sac,  and  are  arranged  in  nearly  parallel 
rings;  they  are  very  strong  about  the  centre,  where  they  often  cause  a con- 
stricted appearance  around  the  stomach,  as  if  dividing  it  into  two  portions; 
the  circular  fibres  again  increase  in  thickness  as  they  approach  the  pylorus ; 
these  fibres  do  not  form  perfect  circles ; the  extremities  of  each  fasciculus 
turn  obliquely  to  one  side;  the  third  set  of  fibres  take  a very  irregular  or 
oblique  direction  ; they  are  most  distinct  on  the  great  end,  or  cul  de  sac,  and 
appear  as  a continuation  of  the  circular  fibres  of  the  oesophagus.  Beneath  the 
muscular  tunic  is  the  second  lamina  of  cellular  tissue,  which  contains  the 
minute  divisions  of  the  nerves  and  vessels  of  the  stomach,  and  has  been,  by 
some,  called  the  nervous  coat  of  the  stomach.  The  internal,  or  mucous  or 
villous  coat  is  very  soft,  and  of  a pale  red  or  rose  color,  sometimes  inter- 
spersed with  such  very  vascular  patches  as  might  lead  the  inexperienced  to 
mistake  them  for  the  effects  of  inflammation : in  otder  to  examine  this  tunic 
of  the  stomach,  this  organ  should  be.  removed  from  the  subject,  everted  and 
washed.  This  membrane  will  be  found  covered  with  a viscid  fluid,  and 
thrown  into  numerous  rugae,  and  will  appear  very  different  from  that  lining 
the  oesophagus;  at  the  pylorus  it  forms  a circular  fold,  which  is  thin  and 
floating;  external  to  this  is  a circular  fasciculus  of  muscular  fibres,  which 
have  a peculiar  dense  feel  : this  fold  of  mucous  membrane  narrows  the  open- 
ing into  the  duodenum,  and  when  assisted  by  the  surrounding  muscular  fibres, 
can  perfectly  intercept  the  passage  from  the  stomach  into  the  intestine  ; in 
the  cellular  tissue,  external  to  this  membrane,  particularly  along  the  curva- 
tures, are  many  small  mucous  glands,  which  open  on  the  mucous  surface; 
these  are  the  glandidac  Brunnerii : the  mucous  coat  of  the  stomach  secretes 
the  fluid  called  the  gastric  juice,  which  is  generally  believed  to  have  the 
remarkable  properties  of  being  powerfully  solvent  and  anti-putrescent.  In 


94 


THE  DUBLIN  DISSECTOR, 


the  stomach  the  food  undergoes  the  first  important  change  in  digestion,  being 
here  converted  into  a soft  homogeneous  pulpy  mass,  called  chyme. 

The  duodenum  is  the  next  portion  of  the  alimentary  canal ; this  is  the  first 
and  shortest  division  of  the  small  intestines ; it  extends  from  the  pylorus  to 
the  root  of  the  mesentery,  where  the  jejunum  commences;  it  lies  partly  in  the 
right  hypochondriac,  and  partly  in  the  right  lumbar  and  in  the  umbilical 
regions;  it  takes  a semicircular  course  around  the  head  of  the  pancreas:  this 
course  may  be  divided  into  three  parts  : the  1st,  or  superior  transverse  ; the 
£d,  or  perpendicular;  and  the  3d,  or  inferior  transverse.  The  superior 
transverse  portion  ascends  from  the  pylorus  obliquely  backwards  and  to 
the  right  side,  beneath  the  edge  of  the  liver,  so  as  to  touch  the  gall  bladder ; 
here  the  intestine  makes  a sudden  turn,  the  superior  angle,  and  the  middle  or 
•perpendicular  portion  of  it  commences  ; this  descends  in  front  of  the  right 
dcidney,  as  low  as  the  third  lumbar  vertebra,  where  it  makes  a second  turn 
(the  inferior  angle)  from  which  the  inferior  transverse  portion  extends  ob- 
liquely upwards,  and  to  the  left  side,  and  at  the  first  lumbar  vertebra  ends  in 
the  jejunum.  The  duodenum  differs  from  the  remainder  of  the  small  intes- 
tine, in  being  fixed  in  its  situation,  and  being  only  partially  covered  by  the 
peritonaeum,  and  being  of  much  larger  caliber,  particularly  near  the  inferior 
angle:  its  muscular  coat  is  very  strong,  and  the  valvulae  conniventes  very 
numerous.  The  superior  transverse  portion  is  more  contracted  than  any 
other  part  of  it;  it  is  covered  on  both  surfaces  by  peritonaeum  like  the 
•stomach,  and  is,  therefore,  more  movable  than  the  rest  of  the  intestine.  The 
•perpendicular  portion  is  concealed  by  the  omentum,  and  by  the  colon,  and  is 
< covered  by  the  ascending  layer  of  the  meso-colon  ; this  portion  lies  on  the 
right  kidney,  and  on  the  vena  cava,  and  has  no  peritonaeum  posterior  to  it;  it 
is  therefore  fixed,  and  is  dilatable  ; the  biliary  and  pancreatic  ducts  perforate 
the  inner  side  of  this  division  of  the  duodenum  : these  pass  through  its  coats 
very  obliquely,  and  open  into  the  intestine,  sometimes  distinctly,  and  at  other 
times  conjointly,  on  a small  papilla,  opposite  the  inferior  angle.  The  inferior 
transverse  part  of  the  duodenum  passes  across  the  aorta  and  the  right  renal 
vessels ; like  the  middle  portion,  it  is  only  partially  covered  by  the  perito- 
nteum,  being  placed  between  the  layers  of  the  meso-colon  ; its  lower  border 
may  be  seen  without  dissection,  projecting  through  the  inferior  layer  of  the 
meso-colon  ; the  superior  mesenteric  vessels  pass  in  front  of  the  termination 
of  this  part  of  the  duodenum,  and  appear  to  compress  it  against  the  aorto,  so 
as  to  retard  the  passage  of  its  contents  into  the  jejunum.  In  the  duodenum, 
the  chyme  is  mixed  with  the  biliary  and  pancreatic  fluids,  and  a separation 
takes  places  between  the  chyle  and  the  excrementitious  part  of  the  food. 

The  jejunum  and  ileum  intestines  are  covered  by  the  omentum  : if  we  raise 
this  process  and  the  arch  of  the  colon,  and  place  them  on  the  edge  of  the 
thorax,  the  convolutions  of  these  intestines  will  be  seen  in  the  umbilical,  hypo- 
gastric, and  iliac  regions  ; convex  anteriorly,  concave  posteriorly,  and  attached 
to  the  mesentery;  the  jejunum  commences  in  the  left  lumbar,  and  the  ileum 
ends  in  the  right  iliac  region.  There  is  no  exact  division  between  these  two 
intestines  ; the  upper  two-fifths  are  named  the  jejunum,  and  are  placed  higher 
in  the  abdomen  than  the  ileum,  which  is  the  name  given  to  the  three  remain- 
ing fifths.  The  jejunum  is  redder,  feels  thicker,  and  is  larger  than  the  ileum, 
which  is  pale  and  thin : these  differences  are  striking,  when  we  compare  the 


OR  MANUAL  OF  ANATOMY. 


95 


commencement  of  the  jejunum  with  the  terminating  portion  of  the  ileum ; 
in  the  intermediate  space,  however  they  are  gradually  lost;  the  greater  vas- 
cularity and  number  of  va'tvulse  conniventes  in  the  jejunum  than  in  the  ileum 
account  for  these  differences  in  these  portions  of  the  alimentary  tube. 

The  large  intestine  forms  about  one-fifth  of  the  intestinal  canal,  and  is  sub- 
divided into  the  caecum,  colon,  and  rectum ; the  large  intestine  differs  from 
the  small,  not  merely  is  size,  but  in  having  a peculiar  cellular  and  sacculated 
appearance,  particularly  when  distended^  small  processes  also  (the  appendices 
epiploicse)  are  attached  along  its  whole  course  ; three  strong  muscular  bands 
running  in  a longitudinal  direction,  may  also  be  observed  chiefly  in  the  csecum 
and  colon ; these  appear  to  pucker  the  large  intestine,  so  as  to  give  it  the 
cellular  structure  before  mentioned : the  large  intestines  are  paler  than  the 
small,  and  much  thinner,  having  but  few  valvulae  conniventes. 

The  csecum,  or  caput  coli,  is  situated  in  the  right  iliac  fossa,  in  which  region 
it  is  fixed  by  the  peritonaeum,  which  in  general  covers  it  only  anteriorly  and 
laterally,  the  cellular  membrane  connecting  it  posteriorly  to  the  iliac  and 
psoas  muscles  ; in  some,  however,  the  peritonaeum  covers  the  csecum  all  round 
and  connects  it  to  the  iliac  fossa  loosely  by  a process,  named  the  meso-caecum ; 
the  caecum  is  covered  anteriorly  by  the  abdominal  muscles,  and  -sometimes 
by  the  convolutions  of  the  ileum;  it  lies  beneath  the  right  kidney,  and  is  con- 
tinuous with  the  ileum  and  the  colon : the  caecum  is  somewhat  triangular,  the 
apex  below,  the  base  above  at  the  colon : on  its  external  surface  are  three 
irregular  protuberances,  one  anteriorly,  and  two  posteriorly ; from  the  lower 
and  posterior  part  of  the  caecum  a small  process,  named  appendix  vermiformis , 
about  the  size  of  a goose  quill,  hangs  into  the  pelvis ; it  is  attached  to  and 
communicates  with  the  caecum  just  below  the  ileum:  a sort  of  mesentery 
connects  it  in  its  situation ; its  use  is  not  ascertained.  The  ileum  joins  the 
left  or  inner  side  of  the  caecum  at  a very  acute  angle  ; it  appears  to  perforate 
the  caecum,  the  peritonaeum  and  external  muscular  fibres  of  the  ileum  being 
continued  into  the  corresponding  parietes  of  the  caecum,  while  the  circular 
fibres  and  mucous  coat  of  the  ileum  protrude  into  the  caecum,  as  may  be  seen 
by  opening  the  latter  in  a perpendicular  direction,  on  the  opposite,  that  is,  on  the 
right  side,  and  washing  out  its  contents  ; we  then  perceive  the  opening  of  the 
ileum,  narrow,  like  a transverse  slit,  looking  obliquely  downwards  and  outwards, 
towards  the  right  ileum,  and  protected  by  two  semilunar  folds  of  mucous 
membrane,  which  enclose  a few  muscular  fibres.  The  inferior  fold,  or  ilio- 
cxcal  valve,  is  the  larger,  is  placed  somewhat  vertical,  and  secures  the  ileum 
against  any  matter  re-entering  it  from  the  caecum,  the  superior  fold,  or  ilio- 
co/ic  valve  is  smaller,  and  placed  rather  horizontal ; it  secures  the  ileum 
against  reguritation  from  the  colon;  these  semilunar  folds  are  united  to  each 
other  at  their  extremities,  ( commissures ) and  from  each  commissure  a promi- 
nent fold  is  continued  round  on  the  inner  side  of  the  caecum:  these  folds  are 
called  the  frajna  or  retinacula  of  these  valves,  in  consequence  of  which,  and 
of  the  commissures,  the  distension  of  the  caecum  closes  the  ilio-caecal  fora- 
men ; the  caecum  is  provided  with  the  same  longitudinal  bands  as  the  colon; 
it  has  no  valvulae  conniventes.  The  colon  extends  from  the  caecum  to  the 
rectum  ; it  is  divided  into  four  portions,  the  right  or  ascending,  the  middle  or 
transverse  arch,  the  left  or  descending,  and  the  sigmoid  flexure ; there  is, 
however,  no  mark  of  distinction  whatever  between  these  different  divisions. 


96 


THE  DUBLIN  DISSECTOR, 


The  ascending  colon  extends  from  the  caecum  to  the  inferior  surface  of  the 
right  lobe  of  the  liver,  which  it  marks  with  a superficial  depression;  this 
portion  of  the  colon  is  concave  anteriorly,  and  covered  by  the  peritonaeum 
and  by  the  abdominal  muscles  ; it  lies  on  the  right  kidney  : the  duodenum  is 
connected  to  it  internally;  the  superior  extremity  is  generally  tinged  with 
bile  from  being  in  contact  with  the  gall  bladder. 

The  transverse  arch  of  the  colon  extends  tortuously  from  the  right  hypo- 
chondrium,  across  the  inferior  part  of  the  epigastric  or  the  umbilical  region 
into  the  left  hypochondrium  ; it  is  covered  by  the  abdominal  muscles,  and  lies 
anterior  to  the  small  intestines:  on  the  right  side  it  is  connected  to  the  liver, 
in  the  middle  to  the  stomach  and  to  the  great  omentum ; and  its  left  extremitv, 
which  is  superior  and  posterior  to  the  right,  is  attached  to  the  spleen  bv  peri- 
tonaeum; the  appendices  epiploicae  are  very  numerous  on  this  part  of  the 
colon. 

The  left  or  descending  colon  extends  from  the  spleen  to  the  left  iliac  region  ; 
it  is  longer  than  the  right  colon  ; it  is  connected  to  the  left  kidney  and  psoas 
muscle  by  the  peritonaeum  and  cellular  membrane. 

The  sigmoid  flexure  is  connected  so  loosely  in  the  iliac  fossa,  that  a great 
portion  of  it  often  lies  in  the  pelvis  : this  part  of  the  colon  is  partiallv  covered 
by  the  small  intestines,  and  is  connected  to  the  psoas  and  iliac  muscles,  to  the 
ureter  and  spermatic  vessels. 

The  rectum  extends  from  the  sigmoid  flexure  of  the  colon  to  the  anus;  it 
commences  opposite  the  left  ilio-sacral  articulation,  and  descends  obliquelv 
towards  the  middle  line  as  far  as  the  lower  end  of  the  sacrum  ; it  then  bends 
forwards  towards  the  perinreum,  and  lastly  turning  downwards,  it  ends  at  the 
anus.  The  rectum  is  connected  posteriorly  to  the  sacrum  and  coccyx  by  the 
meso-rectum  superiorly,  and  by  vessels  and  nerves  interiorly  : anteriorly  the 
rectum  is  connected  to  the  peritonaeum  above,  and  below,  in  the  male  subject, 
to  the  inferior  fundus  of  the  bladder,  the  vesiculae  seminales,  and  the  prostrate 
gland  ; in  the  female  to  the  uterus  and  vagina:  along  the  sides  of  the  rectum 
is  a considerable  quantity  of  cellular  tissue,  and  several  vessels,  particular!  v 
tortuous  veins ; interiorly  the  levatores  ani  muscles  cover  the  sides  of  this 
intestine,  and  its  lower  extremity  is  surrounded  by  the  orbicular  and  cuta- 
neous sphincters.  The  rectum  is  separated  from  the  bladder  in  the  male,  and 
from  the  uterus  in  the  female  by  the  cul  de  sac  of  the  peritonaeum,  which 
may  or  may  not  contain  some  of  the  small  intestines  according  to  the  state  of 
the  pelvic  viscera;  the  rectum,  therefore,  is  only  partially  covered  by  perito- 
naeum; in  the  superior  third  this  membrane  covers  the  intestine  all  around, 
forming  the  meso-rectum  behind  it;  in  the  middle  third  the  peritonaeum  is 
only  connected  to  the  forepart,  and  somewhat  to  its  sides ; and  its  inferior 
third  is  wholly  unattached  to  this  membrane.  The  rectum  is  not  sacculated 
like  the  colon;  it  is  found  in  general  much  dilated  about  an  inch  above 
the  anus. 

In  order  to  examine  the  structure  of  the  intestinal  canal,  let  the  student 
remove  the  following  portions  of  intestine,  including  each  part  between  liga- 
tures, having  first  distended  them  with  air;  a portion  of  duodenum,  of 
jejunum  near  its  commencement,  of  ileum  near  its  termination,  of  the  arc!, 
of  the  colon,  and  of  the  upper  part  of  the  rectum; — 1st,  the  duodenum 
possesses  three  coats  coonected  to  each  other  by  cellular  membrane  ; the 


0!\  MANUAL  OF  ANATOMY. 


9 7 


peritonaeal  or  serous,  the  muscular  and  the  mucous  ; the  first  has  been  already 
mentioned  as  giving  but  a partial  covering  to  this  intestine ; the  muscular  coat 
of  the  duodenum  is  formed  of  strong  red  fibres,  which  take  a circular  direc- 
tion ; there  are  very  few  longitudinal  fibres  to  be  observed  along  it,  except  on 
the  superior  transverse  portion  : lay  open  a part  of  this  intestine,  and  the 
internal  mucous  coat  will  be  found  like  that  of  the  stomach,  thrown  into  soft 
folds  which  lie  nearly  parallel  to  each  other  in  a circular  direction;  these  are 
named  valvulae  conniventes.  2d,  The  jejunum  and  ilieum  also  possess  three 
tunics  and  intermediate  cellular  tissue;  the  serous  or  peritonaeal  coat  almost 
perfectly  surrounds  it,  except  the  small  triangular  space  along  the  concave 
side  where  the  vessels  and  nerves  divide,  and  which  space  admits  of  the  more 
easy  distension  of  the  intestine  ; the  muscular  coat  is  not  so  strong  as  on  the 
duodenum,  but  more  evidently  consists  of  two  sets  of  fibres:  the  longitu- 
dinal are  the  most  superficial,  they  are  very  pale  and  indistinct,  except  along 
the  anterior  or  convex  side  of  the  intestine;  the  circular  fibres  lie  beneath 
these  ; they  are  more  distinct,  but  also  very  pale : no  fibre  passes  perfectly 
round  the  tube.  The  mucous  coat  is  paler  than  in  the  stomach,  and  is  thrown 
into  numerous  folds,  particularly  in  the  jejunum  ; these  folds  are  smaller  and 
less  numerous  in  the  ileum  ; the  muscular  coat  in  the  latter  intestine  also  is 
paler  and  weaker  than  in  the  former.  The  folds  of  mucous  membrane,  called 
valvulae  conniventes,  are  larger  in  the  jejunum  than  in  the  duodenum  or  ileum ; 
in  the  first  they  will  be  found  to  be  a quarter  of  an  inch  deep  in  some  situa- 
tions; in  others,  however,  much  less;  they  form  arches  which  encircle  about 
three-fourths  of  the  intestine,  and  end,  some  in  a point,  others  are  forked  or 
pass  off  obliquely  into  adjacent  folds:  these  valves  are  of  use  in  delaying  the 
food  in  its  passage  along  the  canal,  thus  affording  to  the  absorbents  a better 
opportunity  to  imbibe  all  the  nutritious  matter  or  the  chyle  it  may  contain  ; 
in  proportion  also  as  the  intestine  becomes  distended,  these  valves  become 
more  tense,  and  project  into  the  canal,  so  as  to  separate  the  food  into  smaller 
portions,  and  thus  expose  the  entire  mass  to  the  action  of  the  absorbents:  on 
each  of  these  valves  are  a number  of  small  conical  projections  called  villi: 
when  these  are  examined  through  a magnifying  glass,  small  pores  are  obser- 
vable; these  are  the  mouths  of  the  lacteal  or  absorbent  vessels.  Very  small 
mucous  glands  are  attached  to  the  external  surface  of  the  mucous  membrane 
of  the  intestine  throughout  its  whole  length  ; larger  glands  may  be  noticed  in 
different  situations,  some  scattered  singly,  others  collected  into  clusters;  the 
former,  or  the  o-landulce  solitariae,  or  Brunneri,  are  most  distinct  in  the  duo- 
denum  ; the  latter,  or  the  grandulae  aggregatae  or  Peyeri,  are  most  obvious  in 
the  ileum,  particularly  near  its  termination.  3d,  The  large  intestine  in  some 
situations,  as  has  been  already  observed,  is  but  partially  covered  by  perito- 
naeum ; this  membrane  is  more  loosely  connected  to  the  transverse  arch  of 
the  colon  than  it  is  to  the  small  intestine,  and  is  unattached  along  two  trian- 
gular spaces,  one  along  the. concave  border  between  the  laminae  of  the  meso- 
colon, the  other  along  the  convex,  between  the  layers  of  the  great  omentum  ; 
this  circumstance  favors  the  distension  of  the  colon.  The  muscular  coat  of 
the  large  intestine  also  consists  of  longitudinal  and  circular  fibres  ; the  former, 
however,  are  collected  into  three  fasciculi,  all  of  which  commence  at  the 
vermiform  process,  and  pass  along  the  caecum  and  colon  to  the  rectum  : on 
this  intestine  the  fibres  separate,  increase  in  thickness  and  number,  and  form 
15 


98 


THE  DUBLIN  DISSECTOR, 


a more  perfect  tunic ; near  the  anus  these  fibres  are  confounded  with  those 
of  the  levator  ani  muscle  of  each  side.  The  internal  or  mucous  coat  of  the 
large  intestine  is  pale,  and  forms  but  few  and  imperfect  folds  ; in  the  rectum 
it  becomes  more  vascular  and  villous,  and  presents  several  longitudinal  folds 
as  also  three  or  four  very  remarkable,  in  a horizontal  direction.  As  the  food 
is  propelled  along  the  intestinal  canal,  the  chyle  is  absorbed  by  the  numerous 
lacteal  vessels  to  which  it  becomes  exposed ; it  is  also  mixed  with  a quantity 
of  fluid  ( succus  intestinalis ) secreted  by  the  mucous  glands,  and  by  vessels 
of  the  mucous  membrane ; in  the  large  intestine  the  food  first  presents  the 
feculent  properties,  and  in  its  passage  along  this  part  of  the  canal,  the  ab- 
sorbent vessels  continue  to  take  up  any  chyle  that  may  have  escaped  the  pre- 
ceding, as  well  as  to  absorb  the  watery  parts  of  the  food. 

The  glandular  viscera  of  the  abdomen  which  are  subservient  to  the  process 
of  digestion  are  the  Liver,  Spleen,  and  Pancreas. 

The  Liver  is  the  largest  secreting  gland  in  the  body;  it  fills  the  right 
hypochondrium,  extends  through  the  anterior  part  of  the  epigastric  region  into 
the  left  hypochondrium  as  far  as  the  cardiac  orifice  of  the  stomach,  beyond 
which  however,  it  frequently  extends,  even  to  the  spleen  ; it  is  situated  below 
the  diaphragm,  and  above  the  right  kidney,  the  stomach,  duodenum  and  lesser 
omentum ; it  is  supported  in  this  situation  by  several  folds  of  peritonaeum, 
termed  ligaments  of  the  liver,  viz,  the  falciform,  round,  right,  left  and  coro- 
nary; these  connect  it  to  the  diaphragm  and  abdominal  muscles,  and  the  les- 
ser omentum  attaches  it  to  the  stomach  and  duodenum. 

The  suspensory  or  falciform  ligament  is  a fold  of  peritonaeum  attached 
anteriorly  by  its  convex  border  to  the  linea  alba,  to  the  rectus  muscle  of  the 
right  side,  and  to  the  diaphragm  ; it  passes  obliquely  backwards  and  to  the 
right  side,  and  is  attached  by  its  posterior  or  concave  edge  to  the  upper  or  convex 
surface  of  the  liver,  on  which  its  laminae  separate,  and  expand  over  each  side 
of  its  organ ; enclosed  in  the  inferior  edge  of  this  fold  is  the  obliterated  um- 
bilical vein,  which  substance  in  the  adult  is  named  the  ligamentum  teris : 
this,  which  is  enumerated  as  the  second  ligament  of  the  liver  ascends  from 
the  umbilicus,  obliquely  backwards,  and  to  the  right  side,  and  is  inserted  into 
a notch  in  the  thin  or  anterior  edge  of  the  liver,  which  notch  is  the  commence- 
ment of  the  umbilical  or  horizontal  fissure  of  the  liver.  The  right  and  left 
lateral  ligaments  are  triangular  folds,  connecting  the  right  and  left  lobes  of 
the  liver  to  the  diaphragm  : the  left  lateral  ligament  lies  anterior  to  the  cardiac 
orifice  of  the  stomach  ; the  right  lateral  ligament  is  directly  above  the  right 
kidney.  The  coronary  ligament  is  situated  at  the  upper  extremity  of  the  fal- 
ciform process,  and  consists  of  two  laminae  of  peritonaeum,  which  separate  from 
each  other,  and  connect  the  superior  thick  edge  of  the  liver  to  the  diaphragm ; 
between  the  laminae  of  this  process  the  liver  is  deprived  of  a serous  covering 
and  is  in  contact  with  the  diaphragm ; this  space  lies  anterior  to  the  inferior 
vena  cava.  The  liver  is  of  an  irregular  form ; it  is  longer  transversely  than  from 
before  backwards ; its  posterior  edge  is  very  thick,  and  in  contact  w'ith  the 
diaphragm  ; its  anterior  edge  is  thin,  convex,  and  on  a level  with  the  edge  of 
the  right  hypochondrium,  and  with  the  lower  part  of  the  epigastric  region  ; 
two  notches  may  be  observed  in  this  edge  ; one  below  the  falciform  ligament 
into  which  the  round  ligament  or  obliterated  umbilical  vein  enters ; the  other 
corresponds  to  the  gall  bladder. 


OR  MANUAL  OF  ANATOMY. 


99 


The  superior  or  anterior  surface  19  smooth  and  convex,  and  divided  by  the 
suspensory  ligament  into  a right  and  left  portion,  and  is  contiguous  with  the 
diaphragm.  The  inferior  surface  is  very  irregular,  marked  by  several  pro- 
jections and  depressions ; the  former  are  called  lobes , and  are  five  in  number, 
viz.  first,  the  great  or  right  lobe ; second,  the  left,  separated  from  the  former 
by  the  horizontal  fissure;  third,  the  spigelian  or  middle -lobe ; this  is  situated 
behind  the  lesser  omentum  and  above  and  behind  the  transverse  fissure,  and 
between  the  oesophagus  and  the  cava ; it  is  connected  to  the  right  lobe  by  two 
roots ; one  is  thin  and  placed  vertically  between  the  fissure  for  the  vena  cava 
and  that  for  the  ductus  venosus;  the  other  is  thick  and  placed  transversely, 
and  is  called  lobulus  caudatus,  or  the  fourth  lobe  of  the  liver;  the  lobulus 
caudatus  is  immediately  behind  the  transverse  fissure,  and  extends  from  the 
spigelian,  along  the  right  lobe  between  the  depressions  marked  by  the  colon 
and  right  kidney.  Fifth,  the  lobulus  quadratus  or  anonymus,  is  at  the  anterior 
part  of  the  right  lobe,  in  front  of  the  transverse  fissure,  and  between  the  gall 
bladder  and  horizontal  fissure.  The  principal  depressions  or  fissures  on  the 
inferior  surface  of  the  liver  are  the  following:  first,  the  transverse  fissure 
which  is  situated  between  the  lobulus  quadratus  and  caudatus,  and  extends 
from  the  horizontal  fissure  transversely  to  the  right;  the  vessels  and  nerves 
of  the  liver  enter  the  gland  in  this  fissure;  second,  the  horizontal  fissure 
extends  from  the  notch  in  the  anterior  edge  of  the  liver,  backwards  and  up- 
wards between  the  right  and  left  lobes  ; the  anterior  part  of  this  fissure  con- 
tains the  obliterated  umbilical  vein,  the  posterior  part  the  obliterated  ductus 
venosus ; third,  the  fissure  for  the  vena  cava  is  between  the  lobulus  spigelii 
and  the  right  lobe ; this,  as  the  anterior  part  of  the  horizontal  fissure,  is  fre- 
quently like  a foramen  in  the  liver,  being  surrounded  by  the  substance  of  the 
gland  ; fifth,  the  depression  for  the  gall  bladder  is  on  the  inferior  surface  of 
the  right  lobe,  and  to  the  right  side  of  the  lobulus  quadratus  ; the  substance 
of  the  liver  is  sometimes  deficient  over  this  bag;  sixth  and  seventh,  superfi- 
cial depressions  on  the  under  surface  of  the  right  lobe ; the  anterior  corres- 
ponds to  the  colon,  the  posterior  to  the  right  kidney  and  its  capsule;  these 
depressions  are  indistinctly  marked  in  some  subjects ; they  are  separated  from 
each  other  by  the  extremity  of  the  lobulus  caudatus ; eighth,  a superficial 
depression  on  the  under  surface  of  the  left  lobe,  corresponding  to  the  anterior 
surface  of  the  stomach ; ninth,  a broad  notch  in  the  posterior  edge  of  the 
liver,  corresponding  to  the  spine  and  to  the  right  crus  of  the  diaphragm ; the 
vense  cavae  hepaticae  leave  the  liver  in  this  situation. 

The  liver  is  of  a peculiar  brown  color,  interspersed  with  yellow  ; in  some 
subjects  it  is  much  darker  than  in  others:  in  the  very  young  it  is  red  and  soft, 
and  in  the  old  it  is  generally  pale  and  yellow,  and  often  hard  and  brittle ; it 
has  two  coats,  a serous  and  fibrous;  the  serous,  or  peritonaea!  tunic  covers  the 
whole  surface  of  the  liver,  except  in  those  situations  where  the  vessels,  either 
open  or  obliterated,  are  situated,  and  between  the  laminae  of  the  coronary 
ligament,  also  in  the  depression,  in  which  the  gall  bladder  is  lodged.  The 
2d,  or  fibrous  coat,  is  the  immediate  capsule  to  the  gland ; it  is  thin,  little 
more  than  condensed  cellular  membrane ; it  is  most  distinct  and  strong  where 
the  serous  coat  is  deficient;  it  covers  the  whole  surface  of  the  liver,  and  ad- 
heres to  it  by  innumerable  shreds  or  processes,  which  pass  into  its  substance; 
it  also  accompanies  those  vessels  of  the  liver  which  enter  or  leave  the  transverse 


100 


THE  DUBLIN  DISSECTOR, 


fissure,  and  forms  a capsule  or  sheath  around  their  ramifications  throughout 
the  entire  organ ; this  sheath  receives  the  name  of  the  capsule  of  Glisson  ; 
it  surrounds  the  vessels  very  loosely,  and  also  encloses  loose  cellular  tissue 
hence  it  is,  that  if  these  vessels  be  divided  by  a perpendicular  incision  through 
the  liver,  they  will  be  found  to  collapse  and  recede;  whereas,  if  the  venae 
cavae  hepaticae,  which  run  from  the  thin  towards  the  thick  edge  of  the  liver, 
be  divided  by  a transverse  incision  through  the  liver,  they  will  not  recede  or 
collapse,  but  remain  perfectly  open,  in  consequence  of  the  absence  of  this 
sheath,  and  of  their  close  adhesion  to  the  substance  of  the  liver.  The  struc- 
ture of  the  liver  consists  of  numerous  small  granulations  of  a brown  and 
yellow  color,  connected  together  by  the  branches  of  the  hepatic  arteries,  veins, 
and  ducts  ; these  grains  are  called  acini  of  the  liver,  in  each  of  them  a branch 
of  the  hepatic  artery  and  vena  porta  terminate,  and  out  of  each  proceed  a 
branch  of  the  hepatic  veins  and  ducts.  Through  the  liver,  therefore,  four  sets 
of  vessels  ramify,  in  addition  to  numerous  lymphatics,  viz.  the  branches  of 
the  hepatic  arteries,  venae  portarum,  hepatic  ducts  and  hepatic  veins:  the 
venae  portarum  are  supposed  to  be  the  vessels  from  which  the  bile  is  secreted  ; 
the  hepatic  arteries  nourish  the  substanceof  the  liver;  the  hepatic  ducts  carrv 
the  bile  from  this  organ,  and  the  vence  cavae  hepatic®  return  the  blood  which 
has  circulated  through  the  liver,  to  the  inferior  venae  cavae,  just  as  this  vessel 
is  passing  through  the  diaphragm.  The  vcnx  cuvse  hepaticac,  three  or  four  in 
number,  are  seen  escaping  from  the  liver  at  the  superior  thick  edge,  behind 
the  coronary  ligament,  and  immediately  joining  the  inferior  or  ascending  veil® 
cavae.  The  three  other  vessels  of  the  liver  may  be  seen  between  the  layers 
of  the  lesser  omentum,  the  artery  lying  to  the  left  side,  the  biliary  duct  to 
the  right,  the  vena  porta  behind  and  between  both;  the  artery  and  vein  de- 
scend obliquely  inwards  towards  the  spine,  behind  the  pancreas.  The  hepatic 
artery  is  a branch  of  the  cteliac  axis,  and  the  vena  porta  commences  in  front 
of  the  last  dorsal  vertebra  and  behind  the  pancreas.  The  right  and  left 
hepatic  duds,  on  clearing  the  transverse  fissure,  unite  anil  form  the  hepatic 
duct,  which  descends  for  about  one  inch  and  a half  along  the  right  side  of  the 
lesser  omentum,  is  then  joined  by  the  cystic  duct,  from  the  gall  bladder : the 
union  of  these  forms  the  ductus  communis  clwledochus ; this  vessel,  about 
three  inches  long,  descends  vertically  behind  the  pylorus,  the  upper  part  of 
the  duodenum  and  the  pancreas,  and  is  imbedded  in  the  substance  of  the 
latter,  about  the  middle  of  the  internal  or  concave  side  of  the  middle  division 
of  the  duodenum,  this  duct  perforates  the  coats  of  this  intestine  in  a very 
oblique  direction,  and  opens  on  a small  papilla  internally,  opposite  the  lower 
angle  of  the  duodenum : as  the  ductus  choledochus  is  about  to  perforate  the 
duodenum,  it  is  in  general  joined  by  the  duct  from  the  pancreas. 

The  gall  bladder  is  situated  in  the  right  hypochondrium  in  a depressing 
on  the  inferior  surface  of  the  right  lobe  of  the  liver:  this  membranous  sac  if  of  a 
pyriform  figure  ; the  large  extremity  of  fundus  being  directed  forwards  and 
downwards ; in  some  persons  it  projects  below  the  liver  against  the  abdo- 
minal muscles;  it  is  generally  contiguous  to  the  pylorus  and  to  the  colon ; 
the  smaller  extremity  or  neck  of  the  gall  bladder  is  directed  upwards,  back- 
wards and  inwards,  is  a little  convoluted,  and  ends  in  the  cystic  due', 
which  is  about  an  inch  and  a half  long:  this  duct  bends  downwards  and 
inwards,  and  joins  the  hepatic  duct  at  an  acute  angle,  the  union  ol  which  forms. 


OR  MANUAL  OF  ANATOMY. 


101 


as  was  before  mentioned,  the  ductus  choledochus.  The  gall  bladder  is  closely 
united  to  the  liver  by  the  peritonaeum,  which  passes  over  it;  also  by  cellu- 
lar membrane  and  small  blood  vessels;  it  is  composed  of  a partial  serous 
and  a perfect  cellular  coat,  and  is  lined  by  a mucous  membrane ; the  latter 
has  a peculiar  honey-comb-like  appearance,  and  in  the  duct  is  disposed  in  a 
spiral  lamina.  This  viscus  serves  as  a reservoir  for  the  bile,  when  this  fluid  is 
not  required  in  the  intestinal  canal.  The  bile  is  secreted  in  the  liver,  and 
flows  down  the  hepatic  duct,  and  if  not  required  in  the  duodenum,  or  if  ob- 
structed in  the  ductus  choledochus,  it  passes  into  the  cystic  duct  to  the  gall 
bladder,  where  it  resides  a longer  or  shorter  time,  during  which  period  its 
watery  part  is  absorbed  ; at  the  end  of  some  time,  when  the  bile,  is  required 
to  assist  in  digestion,  it  is  forced  out  of  the  gall  bladder,  and  then  flows  again 
along  the  same  cystic  duct  to  the  ductus  choledochus,  and  so  to  the  duodenum. 
The  bile  is  not  secreted  in  the  gall  bladder,  nor  can  it  possibly  enter  or  leave 
this  viscus  by  any  other  channel  than  though  the  cystic  duct. 

The  Spleen  is  situated  in  the  lefthypochondrium,  between  the  stomach  and 
the  ribs,  beneath  the  diaphragm,  and  above  the  kidney  and  the  colon:  it  is 
connected  to  the  diaphragm  by  the  peritonseum,  also  to  the  stomach  and  pan- 
creas by  vessels  and  by  the  peritonaeum.  The  spleen  is  somewhat  oval ; con- 
vex towards  the  ribs  and  concave  towards  the  stomach  ; on  the  latter  surface 
there  are  several  holes,  and  about  the  centre  of  it  a depression  or  fissure  for 
the  entrance  and  exit  of  blood-vessels ; all  this  surface,  however,  is  not  concave, 
the  part  anterior  to  the  vessels  only  being  so,  while  the  part  posterior  to  them  is 
convex ; the  color  of  the  spleen  is  somewhat  purple  or  livid;  it  is  covered 
by  peritonaeum,  and  beneath  this  by  a fibrous  capsulae,  which  invests  its  entire 
surface,  and  also  passes  into  its  substance  along  with  the  blood-vessels,  and 
assists  in  forming  the  cells  of  which  this  organ  is  composed:  these  cells  are 
found  to  contain  a quantity  of  blood,  partly  coagulated ; also  a number  of 
small  grains,  which  may  be  separated  by  maceration,  but  the  nature  of  which 
is  not  well  understood ; the  spleen  has  no  excretory  duct.  The  exact  use  or 
function  of  this  viscus  is  not  yet  ascertained  ; sometimes  two  or  more  small 
bodies,  of  the  same  color  and  structure  as  the  spleen,  are  found  in  its 
vicinity,  between  the  laminae  of  the  omentum. 

The  Pancreas  lies  behind  the  stomach,  and  may  be  exposed  by  dividing  the 
great  omentum  below  the  stomach,  and  raising  the  latter  organ  towards  the 
thorax.  This  conglomerate  gland  is  of  great  length,  about  seven  inches  long, 
and  about  an  inch  and  a half  broad ; it  extends  from  the  lower  part  of  the  left 
hypochondriac  and  epigastric  regions,  obliquely  downwards  and  forwards 
into  the  umbilical  region,  where  it  is  surrounded  by  the  duodenum  ; it  is  covered 
by  the  stomach  and  the  ascending  layer  of  the  meso-colon  ; it  lies  anterior  to 
the  left  crus  of  the  diaphragm,  the  vena  porta,  and  aorta,  and  overlaps  the 
concave  border  of  the  duodenum,  to  which  it  adheres  very  closely.  The  splenic 
or  left  extremity  (its  tail)  is  small,  compared  with  the  right,  which  is  broad 
and  flat,  and  is  named  the  head  ; the  anterior  surface  looks  a little  upwards, 
the  inferior  edge  being  raised  forwards  by  the  superior  mesenteric  artery 
and  vein,  which  pass  behind  it ; a groove  may  be  remarked  on  the  posterior 
and  upper  part  of  the  pancreas ; this  contains  the  splenic  artery  and  vein. 
The  pancreatic  duct  may  be  seen  by  scraping  off  a l ittle  of  the  posterior  sur- 
face of  the  gland  about  its  centre.  This  duct  is  remarkably  white  and  thin ; it 


102 


THE  DUBLIN  DISSECTOR, 


commences  in  the  small  extremity  of  the  gland,  and  extends  to  the  large  end, 
receiving  in  its  course  numerous  branches  on  each  side : it  usually  joins  the 
ductus  choledochus ; it  sometimes,  however,  opens  into  the  duodenum  distinctly; 
attached  to  the  head  of  the  pancreas  there  is  sometimes  a glandular  mass 
of  the  same  structuie  as  the  pancreas,  and  opening  by  a small  vessel  in  the 
pancreatic  duct;  this  is  named  thg  lesser  pancreas.  The  pancreatic  fluid  is 
supposed  to  be  of  use  in  diluting  the  bile,  and  rendering  it  and  the  contents  of 
the  duodenum  more  miscible  with  each  other.  The  structure  of  the  pancreas 
is  similar  to  that  of  the  salivary  glands,, and  is  thence  called  by  some,  the 
abdominal  salivary  gland, 

OF  THE  VESSELS  AND  NERVES  OF  THE  ABDOMEN. 

The  abdominal  aorta  gives  off  three  large  branches  to  supply  the  organs  of 
digestion,  viz.  the  cceliac  axis,  the  superior  mesenteric  and  inferior  mesenteric 
arteries.  The  cceliac  axis  may  be  seen  by  tearing  through  the  lesser  omentu  in 
above  the  lesser  curvature  of  the  stomaci,  to  arise  from  the  forepart  of  the 
aorta,  at  the  upper  edge  of  the  pancreas ; it  is  about  half  an  inch  long,  and 
divides  into  three  branches,  viz.  the  gastric,  hepatic  and  splenic ; the  gastric 
artery  and  its  branches  run  between  the  laminae  of  the  lesser  omentum,  along 
the  concave  edge  of  the  stomach,  and  supply  both  surfaces  of  this  organ.  The 
hepatic  artery  accompanies  the  vena. porta  and  the  biliary  duct  to  the  trans- 
verse fissure  of  the  liver,  first  sending  off  a small  branch  to  the  pylorus  (pvlo- 
rica  superior,)  next  a large  branch  (gastro-duodenalis,)  which  descends  behind 
the  pylorus  and  subdivides  into  two  branches,  the  pancreatico  duodenalisand 
gastro-epiploica  dextra;  the  former  supplies  the  pancreas  and  duodenum  ; the 
latter  runs  along  the  convex  edge  of  the  stomach,  betw’een  the  layers  of  the 
great  omentum;  the  hepatic  artery  then  divides  into  the  right  and  left  hepatic 
arteries  which  supply  the  right  and  left  lobes  of  the  liver;  the  right  hepatic 
is  the  larger,  and  gives  off  a small  branch,  arteria  cystica,  to  the  gall  bladder. 
The  splenic  artery  is  the  longest  and  largest  branch  of  the  cceliac  axis ; it 
passes  along  the  upper  and  posterior  part  of  the  pancreas,  to  which  it  gives 
many  branches ; near  the  spleen  it  sends  off  the  gastro-epiploica  sinistra,  which 
runs  along  the  convex  edge  of  the  stomach,  between  the  layers  of  the  great 
omentum ; the  splenic  artery  then  divides  into  five  or  six  branches,  which 
enter  the  foramina  in  the  concave  surface  of  the  spleen : from  these  splenic 
branches  five  or  six  small  arteries,  the  vasa  brevia,  pass  to  the  left  or  great 
end  of  the  stomach.  The  superior 'mesenteric  artery  arises  about  half  an  inch 
below  the  cceliac  axis,  behind  the  pancreas  ; it  descends  in  front  of  the  duode- 
num, enters  the  mesentery,  and  bends  obliquely  towards  the  right  iliac  fossa; 
from  its  left  or  convex  side  it  sends  oft'  sixteen  or  eighteen  branches,  which 
supply  the  jejunum  and  the  ileum,  and  from  its  concave  or  right  side  arise  three 
branches,  the  ileo-colica,  colica  dextra,  and  colica  media  ; these  arteries  supply 
the  corresponding  portions  of  the  colon.  The  inferior  mesenteric  artery  arises 
a little  above  the  division  of  the  aorta  into  the  iliap  vessels:  it  descends  to  the 
left  side,  and  divides  into  three  branches.  1st,  The  colica  sinistra,  v.hich 
supplies  the  left  lumbar  colon,  and  inosculates  with  the  colica  media:  2d, 
the  sigmoid  artery,  which  supplies  the  sigmoid  flexure  of  the  colon;  and  3d, 
the  superior  hsemorrhoidal,  which  is  distributed  to  the  rectum. — These  arteries 


OR  MANUAL  OF  ANATOMY. 


103 


are  accompanied  by  corresponding  veins,  which  all  unite  to  form  the  vena 
porta ; the  inferior , mesenteric  vein  accompanies  the  artery  of  that  name  to 
the  aorta,  and  there  joins  the  superior  mesenteric  vein,  which  is  a very  con- 
siderable vessel ; this  common  trunk  then  ascends  behind  the  pancreas,  and 
is  joined  by  a very  large  vein  from  the  spleen  ; the  confluence  of  the  splenic 
and  mesenteric  veins  forms  the  commencement  of  the  vena  porta:  this  vessel 
ascends  obliquely  to  the  right  side,  surrounded  by  nerves  and  cellular  mem- 
brane, and  enclosed  in  the  lesser  omentum ; near  the  transverse  fissure  it 
becomes  dilated  (the  sinus  of  the  porta)  and  then  divides  into  the  right  and 
left  branches ; the  former  is  the  larger,  the  latter  the  longer  of  the  two ; each 
branches  out  through  the  liver,  surrounded  by  the  capsule  of  Glisson,  and  runs 
in  a transverse  direction;  injection  shows  their  minute  branches  to  communi- 
cate in  the  acini  with  the  poribiliarii,  or  with  the  commencements  of  the  hepatic 
ducts. 

The  nerves  which  supply  the  digestive  organs  are  the  8th  pair,  and  the 
splanchnic  branches,  from  the  sympathetic:  the  Sth pair  descend  along  the 
oesophagus,  and  are  distributed  almost  wholly  to  the  stomach;  some  few  branches 
pass  along  the  lesser  omentum  to  the  liver.  The  splanchnic  nerves  are  two  in 
number,  a right  and  left;  they  are  each  formed  by  filaments  from  the  dorsal 
ganglions  of  the  sympathetic  nerve  in  the  thorax  ; they  enter  the  abdomen 
either  along  with  the  aorta,  or  perforate  the  crura  of  the  diaphragm  on  either 
side  of  that  vessel ; in  the  abdomen  each  nerve  soon  ends  in  a large  ganglion, 
the  semilunar  ganglion,  from  which  numerous  brandies  pass  across  the  aorta, 
around  the  coeliac  axis,  and  communicating  with  each  other,  form  the  nervous 
plexus,  named  solar  or  caeliac plexus,  from  which  a fasciculus  of  nerves  extends 
along  each  of  the  branches  of  coeliac  artery  to  supply  the  viscera  in  the  epigas- 
tric region;  thus  a few  accompany  the  gastric  artery  and  communicate  with 
the  8th  pair  on  the  stomach;  several  surround  the  hepatic  artery,  and  by  it 
are  conducted  to  the  liver;  in  like  manner  others  also  pass  to  the  spleen. 
From  the  lower  part  of  the  solar  plexus  several  large  branchesdescend  and 
become  attached  to  the  superior  and  inferior  mesenteric  arteries,  form  plex- 
uses around  these  vessels,  and  receive  additional  branches  from  the  lumbar  or 
abdominal  ganglions  of  the  sympathetic  ; these  nerves  then  twine  around  tli- 
mesenteric  arteries  and  their  branches,  and  are  thus  conducted  to  the  intes- 
tines, in  the  internal  tunic  of  which  they  terminate.  (See  Anatomy  of  the 
Nervous  System.)  The  student  may  now  remove  the  abdominal  viscera. 
Tie  the  lower  extremity  of  the  oesophagus  and  the  upper  end  of  the  rectum, 
each  with  two  ligatures,  and  divide  these  tubes  between  them:  dissect  out 
the  vena  cava  from  the  liver,  cut  across  the  hepatic  vessels,  the  coeliac  axis, 
the  superior  and  inferior  mesenteric  arteries  ; and  then  separate  the  liver, 
spleen,  pancreas,  and  alimentary  canal,  from  their  connections  to  the  parietes 
of  the  abdomen  ; next  clean  the  surface  of  the  abdominal  aorta  and  vena  cava, 
the  right  and  left  kidney,  and  the  renal  capsules.  The  abdominal  aorta  may 
be  now  seen  to  pass  into  the  abdomen,  between  the  crura  of  the  diaphragm, 
opposite  the  last  dorsal  vertebra  ; it  then  descends  obliquely  to  the  left  side, 
and  divides  on  the  body  of  the  fourth  lumbar  vertebra  into  the  right  and  left 
iliac  arteries.  The  abdominal  aorta  sends  off  the  following  branches : 1st,  the 
two  phrenic  arteries ; 2d,  the  coeliac  axis  ; 3d,  the  superior  mesenteric  artery ; 
4th,  the  two  renal  arteries;  5th,  the  spermatic  arteries;  6th,  the  inferior 


104 


THE  DUBLIN  DISSECTOR, 


mesenteric  artery  ; also  four  or  five  pair  of  lumbar  arteries  from  its  posterior 
part;  and  lastly,  from  the  angle  of  its  division  the  middle  sacral  artery  de- 
scends. The  right  and  left  iliac  arteries  descend  obliquely  outwards  and 
backwards ; that  of  the  right  side  is  the  longer  of  the  two ; opposite  each  ilio- 
sacral  articulation  each  common  iliac  artery  divides  into  the  internal  and  ex. 
ternal  iliac.  The  external  proceeds  along  the  inner  side  of  the  psoas  magnus, 
and  passing  beneath  Poupart’s  ligament,  becomes  the  femoral  artery;  just 
above  this  ligament  it  sends  off"  two  branches,  the  epigastric  and  the  circum- 
flex ilii.  The  internal  iliac  artery  descends  into  the  pelvis,  and  gives  off 
several  branches,  which  shall  be  noticed  afterwards  in  the  dissection  of  that 
cavity.  The  veins  in  the  abdomen  correspond  to  the  arteries  ; each  external 
iliac  vein  ascends  along  the  inner  side  of  the  artery  of  the  same  name,  and 
near  the  sacrum  is  joined  by  the  internal  iliac  vein , which  ascends  from  the 
pelvis;  the  union  of  these  on  each  side  form  the  common  iliac  veins;  each 
of  these  ascends  behind  its  accompanying  artery,  and  opposite  the  right  side 
of  the  fourth  or  fifth  lumbar  vertebra  these  veins  unite  and  form  the  inferior 
or  ascending  vena  cava  ; the  left  common  iliac  vein  is  longer  than  the  right, 
and  passes  behind  the  right  iliac  artery.  The  vena  cava  ascends  along  the 
right  side  of  the  aorta,  and  receives  the  spermatic,  renal,  and  lumbar  veins; 
it  lies,  interiorly,  on  the  right  psoas  muscle,  and  on  the  right  crus  of  the  dia- 
phragm; superiorly,  it  inclines  forwards  and  to  the  right  side,  and  enters  the 
fissure  in  the  liver;  here  it  receives  the  vense  cavae  hepaticse  ; it  then  passes 
through  the  opening  in  the  tendon  of  the  diaphragm,  and  arrives  at  the  right 
auricle  of  the  heart.  On  each  side  of  the  abdominal  aorta  the  sympathetic 
nerves  may  be  seen  ; they  pass  from  the  thorax  into  the  abdomen,  beneath  the 
true  ligamentum  arcuatum,  and  then  descend  between  the  crus  of  the  dia- 
phragm and  the  psoas  magnus  on  each  side  ; in  this  course  they  form  three  or 
four  oval  ganglions.  At  the  last  lumbar  vertebra  these  nerves  pass  outwards 
and  backwards,  and  then  descend  into  the  pelvis. 

The  commencement  of  the  vena  azygos  may  be  observed  on  the  right  side 
of  the  aorta ; it  is  formed  by  the  first  or  second  lumber  veins,  which  communi- 
cate with  the  renal  and  inferior  lumbar  veins,  and  sometimes  w ith  the  inferior 
vena  cava.  The  vena  azygos  enters  the  thorax  between  the  aorta  and  the 
right  crus  of  the  diaphragm,  and  then  ascends  along  the  posterior  mediasti- 
num. The  thoracic  duct  also  may  be  seen  to  commence  in  the  abdomen  by 
the  union  of  several  absorbent  vessels  on  the  body  of  the  third  lumbar  verte- 
bra; this  vessel,  being  larger  here  than  it  is  above,  has  received  the  name  of 
receptaculum  chyli : this,  however,  does  not  always  exist.  The  thoracic  duct 
is  covered  at  first  by  the  aorta,  it  then  ascends  obliquely  to  the  right  side,  and 
enters  the  thorax  between  the  aorta  and  vena  azygos.  Let  the  student  next  ex- 
amine the  urinary  organs ; these  consist — 1st,  of  the  kidneys,  which  secrete  the 
urine  ; 2d,  of  the  ureters,  which  convey  this  fluid  to  3d,  the  urinary  bladder, 
which  retains  it  for  a longer  or  shorter  time;  and  4th,  the  urethra,  which 
discharges  it  externally. 

DISSECTION  OF  THE  KIDNEYS  AND  URETERS. 

Each  kidney  is  situated  in  the  posterior  part  of  each  lumbar  region,  behind  the 
peritonaeum,  between  the  last  rib  and  the  cr  est  of  the  ilium  ; and  corresponds 


OR  MANUAL  OF  ANATOMY, 


105 


to  the  two  last  dorsal  and  two  first  lumbar  vertebrae;  the  right  kidney 
is  often  a little  lower  than  the  left,  particularly  if  the  liver  be  larger  than 
usual ; they  are  each  imbedded  in  a quantity  of  soft  adipose  substance,  and 
lie  on  the  diaphragm,  psoas,  and  quadratus  lumborum  muscles;  the  ascending- 
colon  and  duodenum  lie  anterior  to  the  right,  and  the  descending  colon  to  the  left 
kidney;  the  right  is  in  contact  with  the  liver  above,  and  with  the  caecum 
below  ; and  the  left  with  the  spleen  above,  and  the  sigmoid  flexure  of  the 
colon  below.  The  anterior  surface  of  each  is  convex,  the  posterior  is  flat;  in 
the  young  subject  the  surfaces  are  very  uneven,  the  kidneys  at  that  age  being 
lobulated.  The  external  border  of  each  is  smooth  and  convex,  and  directed 
outwards  and  backwards ; the  concave  edge  is  of  much  less  extent,  looks 
forwards  and  inwards,  and  contains  the  arteries,  veins,  and  excretory  duct ; 
the  veins  are  usually,  but  by  no  means  constantly,  anterior;  the  arteries,  five 
or  six  in  number,  are  behind  these  ; and  the  ureter  is  posterior  and  inferior  to 
both.  The  superior  extremity  of  each  kidney  is  larger  and  nearer  to  the  spine 
than  the  inferior.  The  kidney  is  partially  covered  by  peritonaeum,  to  which 
it  is  but  loosely  connected  ; it  has  also  a capsule  of  cellular  and  adipose  sub- 
stance, and  a strong  smooth  fibrous  tunic,  which  adheres  closely  to  its  sub  - 
stance, preserves  its  form,  and  is  continued  into  its  interior,  along  the  vessels, 
as  far  as  the  calyces  of  the  kidney.  Remove  one  kidney  from  the  subject, 
and  divide  it  by  a perpendicular  incision  from  the  convex  to  the  concave  edge, 
the  gland  will  then  be  found  to  consist  of  two  distinct  substances,  the  exter- 
nal or  vascular,  the  internal  or  membranous.  The  external,  vascular,  or  cor- 
tical substance,  forms  a covering  for  the  kidney  about  two  lines  thick,  and 
sends  longer  prolongations  into  the  body  of  the  gland  ; between  the  tubular 
fasciculi.  The  cortical  substance  is  of  a dark  brown  red  color,  and  can  be 
separated  into  numerous  small  grains;  when  injected  it  seems  wholly  com- 
posed of  arteries  and  veins.  Internal  to  this  is  the  tubular  substance , which  con- 
sist of  fine  vessels  of  a pale  color,  and  very  dense  structure  ; these  are  arranged 
in  conical  fasciculi,  about  eight  or  ten  in  number;  the  base  of  each  is  directed 
towards  the  circumference,  the  apex  towards  the  concave  edge  of  the 
kidney:  the  apices  of  these  cones  are  named  papillx;  each  papilla  is  perfo- 
rated by  several  small  holes,  through  which  the  urine  may  be  observed  to  flow 
when  the  tubular  cones  are  compressed.  The  papillae  are  surrounded  by 
membranous  sacs  called  calyces ; each  calyx  contains  one  or  two  papillae  and 
are  five  or  six  in  number;  they  are  dense  and  white,  composed  externally 
of  a fibrous  coat  of  the  kidney,  and  internally  of  a fine  mucous  membrane, 
which  is  continued  from  the  ureter  along  the  pelvis  of  the  kidney,  lines  all 
the  calyces,  and  is  reflected  in  the  form  of  a very  fine  membrane  over  each 
papilla,  and  most  probably  is  continued  into  the  tubuli  uriniferi.  The  calyces 
in  each  extremity,  as  also  those  in  the  centre  unite  into  three  small  tubes, 
which  being  of  a funnel  shape,  are  called  infundibula  ; these  have  but  a short 
course,  and  soon  terminate  in  the  pelvis  of  the  kidney.  The  pelvis  is  a mem- 
branous reservoir  formed  by  the  union  of  the  calyces  or  the  infundibula  of  a 
flattened  oval  figure,  placed  behind  the  blood-vessels  of  the  kidney,  and  ter- 
minating in  the  ureter,  which  it  resembles  in  structure.  Each  kidney  receives 
a very  large  artery  (the  renal  or  emulgent)  from  the  aorta : this  divides 
into  six  or  eight  branches,  which  enter  the  notch  in  the  gland,  subdivide  into 
numerous  fine  vessels,  which  proceed  between  the  tubular  portions  to  the 
14 


106 


THE  DUBLIN  DISSECTOR, 


cortex,  in  which  they  terminate  in  minute  branches,  some  of  which  are  continu- 
ous with  corresponding  veins,  others  with  the  commencements  of  the  tubular 
fasciculi;  these  last  separate  the  urine  from  the  blood,  and  pour  it  into  the 
tubuli  uriniferi,  which  convey  it  to  the  papilla;,  through  the  small  pores  of  which 
it  gradually  flows  into  the  calyces,  and  from  these  into  the  pelvis,  and  so  into 
the  ureter.  The  ureter  is  the  excretory  duct  of  the  kidney,  and  extends  from 
it  to  the  urinary  bladder;  each  ureter  is  about  eighteen  inches  long,  and  about 
the  size  of  a goose  quill ; its  coats  are  very  pale,  and  always  appear  collapsed . 
These  vessels  take  an  oblique  course  downwards  and  inwards  to  the  pelvis  ; 
each  then  inclines  a little  forwards,  continuing  still  to  run  downwards  and  in- 
wards to  the  inferior  and  posterior  part  of  the  bladder,  passes  obi  iquely  between 
the  muscular  and  mucous  coats  of  this  viscus ; and  perforates  the  latter  at  the 
posterior  angle  of  the  trigone.  Each  ureter  passes  anterior  to  the  psoas  mag- 
nus,  and  to  the  iliac  vessels,  is  covered  by  the  peritonaeum,  and  crossed  by 
the  spermatic  vessels,  and  near  its  termination  in  the  male  subject  by  the  vas 
deferens  ; and  in  the  female  by  the  fallopian  tubes,  and  broad  ligaments  of  the 
uterus.  In  the  male  each  ureter  attaches  itself  to  the  bladder  at  the  posterior 
extremity  of  each  vesicula  seminalis,  and  runs  for  the  extent  of  an  inch  be- 
tween the  tunics  of  the  bladder,  and  opens  internally  (as  will  be  seen  hereaf- 
ter in  the  dissection  of  the  pelvic  viscera)  about  an  inch  and  a half  from  the 
commencement  of  the  urethra,  and  about  the  same  distance  from  its  fellow. 
In  the  female  the  pelvic  portion  of  each  ureter  is  longer  than  the  male  ; they 
also  lie  at  a greater  distance  from  each  other,  and  perforate  the  bladder  nearer 
to  its  neck  than  in  the  male  subject.  The  ureter  is  composed  externally  of 
a fibrous  coat  and  internally  of  a pale  mucous  membrane  ; it  is  surrounded  by 
cellular  tissue,  and  in  some  situations  is  partially  covered  by  peritonaeum.  The 
ureters  are  larger  at  their  commencement,  and  smaller  at  their  termination  ; 
the  intermediate  portion  of  each  is  nearly  of  one  uniform  diameter. 

Attached  to  the  upper  extremity  of  each  kidney  is  a small  gland-like  sub- 
stance, named  renal  capsule , or  supra-renal,  or  atrabiliary  body  ; of  a crescentic 
shape,  the  base  attached  to  the  kidney  by  cellular  membrane  and  by  small 
blood-vessels;  these  organs  lie  on  the  diaphragm,  and  on  the  semilunar  gang- 
lion of  each  side,  and  are  covered,  that  on  the  right  side  by  the  vena  cava  and 
duodenum,  and  on  the  left  by  the  spleen  and  pancreas ; a vein  also  runs  along 
their  anterior  surface.  In  the  interior  of  each  renal  capsule  we  find  a small 
triangular  cavity  filled  with  a brownish  fluid  ; the  walls  of  this  cavity  are 
very  rough,  no  excretory  duct  can  be  found  leading  from  it.  The  exact  use 
of  these  bodies  is  not  ascertained.  The  renal  capsules  in  the  adult  are  thin, 
and  of  a brownish  yellow  color;  in  the  foetus  they  are  very  large  and  vascu- 
lar, nearly  equal  to  the  kidney  in  size,  and  contain  a quantity  of  reddish 
fluid. 

The  bladder  and  urethra  are  the  next  divisions  of  the  urinary  organs  to  be 
examined  ; as  these,  however,  are  pelvic  viscera,  we  shall  postpone  the  con- 
sideration of  them  for  the  present,  and  the  student  should  next  examine  the 
deep  muscles  of  the  abdomen,  viz.  the  diaphragm,  and  the  quadratus  lumbo- 
rum,  psoas  parvus,  psoas  magnus,  and  iliacus  internus  of  each  side. 


OR  MANUAL  OF  ANATOMY. 


107 


DISSECTION  OF  THE  DEEP  MUSCLES  OF  THE  ABDOMEN. 

Diaphragm  is  exposed  by  dissecting  off  the  peritonaeum ; it  separates  the 
abdomen  from  the  thorax,  being  concave  towards  the  former  cavity,  convex 
towards  the  latter;  it  may  be  divided  into  two  portions,  a superior  broad  por- 
tion (the  true  diaphragm)  and  the  inferior  lesser  portion,  or  the  appendices 
or  crura  of  the  diaphragm.  The  superior  true  diaphragm  is  broad,  thin,  and 
nearly  circular;  it  arises  by  distinct  fleshy  fasciculi,  from  the  posterior  sur- 
face of  the  xiphoid  cartilage,  and  from  the  internal  surface  of  the  cartilages  of 
the  last  true,  and  of  all  the  false  ribs;  these  fasciculi  indigitate  with  those  of 
the  transversalis  muscle  ; between  the  extremity  of  the  last  rib  and  the  side 
of  the  spine,  it  arises  from  the  upper  part  of  a strong  aponeurosis,  which  covers 
the  quadratus  lumborum  muscle  ; this  is  the  anterior  lamina  of  the  tendon  of 
the  transversalis ; the  upper  edge  of  this  fascia  being  very  tense,  particularly 
'when  the  13th  rib  is  everted,  and  appearing  to  be  extended  as  a distinct  liga- 
ment between  this  bone  and  the  first  lumbar  vertebra,  has  received  the  name 
of  the  // g amentum  arcuatum  ; it  is  not  a distinct  ligament ; it  may,  however, 
be  named  the  external  or  false  ligamentum  arcuatum,  to  distinguish  it  from 
a true  and  distinct  ligament,  which  extends  from  the  transverse  process  of 
the  first  to  the  body  of  the  second  lumbar  vertebra;  this  may  be  named  the 
true  or  internal  ligamentum  arcuatum;  its  concavity  looks  downwards,  and 
extends  across  the  upper  extremity  of  the  psoas  magnus  and  the  sympathetic 
nerve ; from  the  convex  edge  of  this  ligament  the  diaphragm  next  arises  ; from 
this  extensive  origin  the  fibres  pass  in  different  directions,  the  anterior  back- 
wards and  upwards  to  the  edge  of  the  cordiform  tendon,  the  middle  upwards 
and  inwards,  and  then  a little  downwards,  to  the  lateral  borders  of  the  cen- 
tral tendon,  and  the  posterior  fibres  pass  forwards  and  upwards  to  the  poste- 
rior edge  of  the  tendon ; the  anterior  fibres  are  the  shortest,  the  lateral  are 
the  longest  and  the  most  arched,  particularly  those  on  the  right  side,  the  con- 
vexity of  which  is  on  a level  with  the.  fourth  rib;  the  convexity  of  those  on 
the  left  side  is  on  a level  with  the  fifth  or  sixth  rib.  The  central  tendon  of 
the  diaphragm  is  of  great  transverse  breadth,  and  is  divided  into  three  por- 
tions, an  anterior,  right  and  left;  the  first  is  the  largest,  the  last  is  the 
smallest;  in  regard  to  their  relative  size  these  divisions  of  the  tendon  are  un- 
certain ; the  posterior  border  of  the  tendon  is  notched  for  the  insertion  of  the 
crUra  or  appendices  of  the  diaphragm;  the  fibres  of  this  tendon  chiefly  run  in 
rays  from  behind,  forwards  and  outwards ; they  are  crossed  and  interlaced, 
however,  by  several  bands,  which  have  an  irregular  direction;  this  tendon  is 
much  stronger  and  larger  in  proportion  in  the  old  than  in  the  young.  Behind 
and  below  this  tendon  are  the  two  crura  or  appendices  of  the  diaphragm ; the 
right  crus  is  longer  and  thicker  than  the  left,  and  arises  by  tendinous  bands 
from  the  forepart  of  the  bodies  of  the  first  four  lumbar  vertebrae.  The  left  is 
smaller,  and  on  a plane  posterior  to  the  right ; it  arises  from  the  sides  of  the  two 
or  three  first  lumbar  vertebrae ; the  fibres  of  each  crus  ascend  obliquely  forwards, 
are  connected  to  each  other  by  a semilunar  tendinous  band  extended  across 
the  aorta;  they  then  become  fleshy,  and  a small  fasciculus  is  sent  from  each 
crus  to  join  the  opposite ; these  decussating  fasciculi  separate  the  oesophageal 
from  the  aortic  opening  in  the  diaphragm ; of  these  fasciculi,  that  from  the 


106 


THE  DUBLIN  DISSECTOR, 


right  crus  is  always  the  larger,  and  that  from  the  left  is  generally,  but  not  al- 
ways anterior.  Each  crus  then  ascends,  and  is  inserted  into  the  posterior 
border  of  the  cordiform  tendon.  The  right  crus  of  the  diaphragm  is  covered 
by  the  vena  cava,  renal  capsule,  semilunar  ganglion,  and  by  the  liver  ; the  left 
crus  by  the  aorta,  left  renal  capsule,  semilunar  ganglion,  spleen,  and  stomach. 
To  the  thoracic  surface  of  this  muscle  the  pleurae  are  attached  laterally,  and 
the  pericardium  and  mediastina  along  the  middle.  Three  large  openings  are 
observed  in  the  diaphragm ; one  for  the  aorta,  one  for  the  vena  cava,  and  one 
for  the  oesophagus.  The  aortic  opening  is  rather  a tendinous  passage,  behind 
and  between  the  crura  of  the  diaphragm;  it  opens  into  the  abdomen  opposite 
the  last  dorsal  vertebra,  and  nearly  in  the  mesial  line;  the  thoracic  duct  and 
vena  azygos  ascend  through  it,  along  the  right  side  of  the  aorta  ; the  splanch- 
nic nerves,  particularly  the  left,  sometimes  pass  through  this  opening;  but  in 
general  these  nerves  perforate  the  crura  at  a little  distance  from  the  aorta. 
The  opening  for  the  oesophagus  and  eighth  pair  of  nerves  is  superior  and  ante- 
rior to  that  for  the  aorta,  and  is  a little  to  the  left  of  it ; it  is  of  an  oval  figure  ; 
its  parietes  are  fleshy,  and  are  formed  by  the  decussating  fasciculi  from  the 
crura;  the  origin  of  these  separate  the  oesophageal  from  the  aortic  opening. 
The  opening  for  the  vena  cava  is  situated  at  the  back  part  of  the  right  divi- 
sion of  the  tendon,  anterior  to  the  insertion  of  the  right  crus;  this  foramen  is 
perfectly  tendinous  ; it  is  somewhat  quadrilateral,  and  appears  larger  than  the 
vein ; the  edges  are  attached  to  the  vessel,  and  prolonged  upon  its  coats  ; the 
anterior  margin  being  continued  on  the  abdominal  portion,  and  the  posterior 
margin  on  the  thoracic  portion  of  the  vein.  Posterior  to  the  ensiform  carti- 
lage there  is  a small  triangular  space  on  each  side,  where  the  diaphragm  is 
deficient,  and  through  which  the  peritonseuin  is  connected  to  the  pleura  and 
pericardium;  through  this  space  also  the  cellular  membrane  in  the  mediasti- 
num is  continuous  with  that  between  the  abdominal  muscles.  Use,  it  is  the 
principal  muscle  in  inspiration;  by  its  action  it  enlarges  the  thorax  in  the 
perpendicular  direction,  for  the  contraction  of  the  crura  draws  down  the 
cordiform  tendon,  and  fixes  it ; and  then,  when  the  fibres  of  the  superior  dia- 
phragm contract,  they  descend,  and  instead  of  being  convex  towards  the 
chest  they  become  nearly  straight,  so  as  to  present  a plane  surface  to  the  ab- 
domen, looking  downwards  and  forwards.  As  the  fleshy  fibres  are  longest  at 
the  sides,  it  is  here  the  greatest  descent  in  the  muscle  occurs,  consequently 
the  thorax  is  most  enlarged  on  each  side  beneath  the  lungs.  When  the  dia- 
phragm relaxes,  its  elasticity  and  the  connection  of  the  pleurae  and  pericardium 
to  its  superior  surface,  cause  it  to  re-ascend,  so  as  to  present  a concave  sur- 
face to  the  abdomen,  and  so  diminish  the  capacity  of  the  thorax.  The 
diaphragm  also  assists  in  coughing,  laughing,  speaking;  also  in  the  expulsion 
of  urine  and  faeces,  and  in  the  various  exertions  of  the  body.  The  student 
may  now  re-consider  the  different  muscles  which  assist,  and  which  oppose  the 
diaphragm  in  respiration;  by  this  term  we  mean  the  act  of  taking  into  the 
lungs  a certain  quantity  of  air,  and  the  subsequent  expulsion  of  it  from  these 
organs;  the  former  is  termed  inspiration,  the  latter  expiration.  Inspiration 
requires  greater  muscular  efforts  than  expiration,  which  is  chiefly  effected  by 
the  relaxation  of  the  muscles  of  inspiration,  and  by  the  elasticity  of  the  pa- 
rietes of  the  thorax.  Inspiration  may  be  performed  with  two  different  degrees 
•of  force  ; the  first,  in  which  there  is  little  muscular  effort,  is  called  ordinary 


OR  MANUAL  OF  ANATOMY. 


109 


inspiration  ; the  second,  in  which  there  is  great  exertion,  is  called  full  inspi- 
ration. In  the  first,  the  diaphragm  and  the  intercostal  muscles  are  employed, 
but  chiefly  the  former;  and  in  the  second,  several  additional  muscles  assist, 
viz.  the  scaleni,  the  subclavian,  the  serrati  postici ; also  by  fixing  the  superior 
extremities,  the  pectoral,  serrati  magni,  and  latissimi  dorsi  muscles  exert 
considerable  power,  in  elevating  the  ribs  and  drawing  them  outwards,  so  as 
to  enlarge  the  chest  transversely,  and  from  before  backwards. 

Expiration  also  may  be  performed  in  the  same  different  degrees  of  intensity ; 
in  the  first  or  ordinary  degree,  the  elasticity  and  slight  contraction  of  the  ab- 
dominal muscles  press  the  viscera  against  the  diaphragm,  which  is  already 
receding  in  consequence  of  its  own  relaxation,  and  the  elasticity  of  the  parts 
attached  to  its  thoracic  surface  : when  expiration  is  performed  in  the  second, 
or  forced  degree,  the  elasticity  of  the  ribs  and  of  their  cartilages  opposes  the 
intercostal  muscles ; the  triangulares  sterni  also  depress  the  cartilages,  and 
the  abdominal  muscles  and  levatores  ani,  by  increasing  their  contracting 
force,  push  the  abdominal  viscera  against  the  diaphragm,  and  draw  down  the 
ribs;  the  serrati  postici  inferiores  and  quadrati  luinborum  muscles  assist,  also 
the  latissimi  dorsi  muscles,  by  acting  towards  the  ilium ; and  should  the  last 
rib  be  fixed,  it  is  possible  for  the  intercostal  muscles  to  depress  the  superior 
ribs,  and  so  to  become  muscles  of  expiration. 

Quadratus  Lumborum,  is  a thick,  fiat  muscle,  between  the  anterior  and 
middle  layers  of  the  transversalis  abdominis  tendon,  posterior  to  the  psoas, 
the  kidney  and  the  diaphragm  ; and  anterior  to  the  sacro-lumbalis  ; it  arises 
tendinous  from  the  posterior  fourth  of  the  spine  of  the  ilium,  and  from  the 
ilio-lumbar  ligament;  the  fibres  ascend  obliquely  inwards,  and  are  inserted 
into  the  extremity  of  the  transverse  processes  of  the  first  four  lumbar  verte- 
brae, and  of  the  last  dorsal ; also  into  the  internal  surface  of  the  posterior 
half  of  the  last  rib.  Use;  to  bend  the  spine  to  one  side,  to  depress  the  last 
rib,  thus  assisting  in  expiration ; when  both  muscles  act,  they  support  the 
spinal  column  in  the  perpendicular  direction. 

Psoas  Parvus  arises  fleshy  from  the  side  of  the  last  dorsal  and  first  lumbar 
vertebra,  ends  in  a long  flat  tendon,  which  descends  on  the  inner  side  of  the 
psoas  tnagnus,  and  is  inserted  broad  and  thin  into  the  linea  ileo-pectinaea,  or 
brim  of  the  pelvis,  also  into  the  fascia  iliaca  and  fascia  lata,  behind  the  femoral 
vessels.  Use  ; it  assists  in  bending  the  body  forwards,  or  in  raising  the  pelvis ; 
it  also  makes  tense  the  crusal  arch,  in  consequence  of  its  attachment  to  the 
fascia  lata.  This  muscle  is  often  wanting ; when  present,  it  is  situated  in- 
ternal and  anterior  to  the  psoas  magnus,  and  is  partly  concealed  by  the  dia- 
phragm, the  renal  vessels,  the  peritonaeum,  and  at  its  insertion  by  the  external 
iliac  artery. 

Psoas  Magnus,  long,  round  and  thick  in  the  centre,  small  at  its  extremities, 
fleshy  at  its  superior,  tendinous  at  its  inferior;  it  extends  along  the  sides  of 
the  lumbar  vertebras,  of  the  brim  of  the  pelvis,  and  the  anterior  and  inner 
part  of  the  thigh  ; it  arises  fleshy  from  the  side  of  the  body  of  the  last  two 
dorsal,  and  from  the  bodies  and  transverse  processes  of  all  the  lumbar  verte- 
brae, also  from  the  intervertebral  ligaments ; the  fibres  all  descend,  at  first 
vertically,  afterwards  obliquely  outwards,  along  the  brim  of  the  pelvis,  and 
beneath  Poupart’s  ligament;  the  muscle  then  becomes  tendinous,  and  de- 
scends obliquely  inwards  and  backwards,  and  is  inserted  tendinous  into  the 


110 


THE  DUBLIN  DISSECTOR, 


back  part  of  the  lesser  trochanter,  also  fleshy  into  a ridge  below  that  process. 
Use;  to  flex  the  thigh  on  the  pelvis,  or  the  body  on  the  thigh;  it  also  rotate> 
the  thigh  outwards ; in  standing  it  supports  the  spine,  and  prevents  it  bending 
backwards,  and  in  walking  it  is  particularly  engaged  ; it  then  raises,  throws 
forwards  and  outwards  the  lower  extremity.  This  muscle  is  situated  between 
the  psoas  parvus  and  the  cjuadratus  lumborum  above,  and  between  the  former 
muscle  and  the  iliacus  below ; and  in  the  groin,  between  the  sartorius  and  the 
pectinaeus : its  insertion  is  between  the  vastus  internus  and  the  pectinseus ; it 
is  covered  in  the  lumbar  region  by  the  diaphragm,  the  kidney,  and  its  vessels  : 
also  on  the  right  side  by  the  vena  cava,  and  on  the  left  by  the  aorta ; in  the 
middle  or  pelvic  division  of  its  course  it  lies  between  the  external  iliac  vessels 
and  the  iliac  muscle  and  the  anterior  crural  nerve;  in  its  lower  or  inguinal 
division  it  is  partly  covered  by  the  femoral  artery  and  nerve,  and  by  some  of 
their  branches,  also  by  the  inguinal  glands,  and  by  a considerable  quantity  of 
cellular  membrane.  The  psoas  lies  anterior  to  the  transverse  processes  of 
the  lumbar  vertebrae,  to  the  quadratus  lumborum,  the  lumbar  nerves,  the  inner 
edge  of  the  iliacus  internus,  and  the  capsular  ligament  of  the  hip;  the  lumbar 
nerves  or  the  lumbar  plexus  in  general  run  through  the  psoas,  perforating  its 
posterior  portion  ; a large  bursa  separates  its  tendon  from  the  pubes  and  from 
the  capsular  ligament;  this  bursa  sometimes  communicates  with  the  synovial 
membrane  of  the  hip  joint.  A smaller  bursa  lies  between  the  point  of  the 
lesser  trochanter  and  this  tendon.  The  tendon  of  the  psoas  is  formed  in  the 
outer  or  iliac  side  of  the  muscle,  and  receives  the  insertion  of  the  fibres  of 
the  iliacus  internus. 

Iliacus  Internus,  flat,  or  concave,  radiated  or  triangular,  arises  fleshy  from 
the  transverse  process  of  the  last  lumbar  vertebra,  from  the  inner  margin  of 
three  anterior  fourths  of  the  crest  of  the  ilium,  from  the  two  anterior  spinous 
processes,  and  from  the  intervening  notch,  from  the  brim  of  the  acetabulum, 
and  from  the  capsular  ligament,  also  from  the  iliac  fossa,  and  from  the  strong 
aponeurosis,  the  iliac  fascia,  which  covers  it.  The  iliac  fascia  is  attached  to 
the  crest  of  the  ilium,  to  Poupart’s  ligament,  as  far  inwards  as  the  iliac  artery, 
behind  which  it  passes  and  becomes  continuous  with  the  pubic  portion  of  the 
fascia  lata;  the  fibres  of  this  muscle  all  descend  obliquely  inwards,  join  the 
outer  side  of  the  tendon  of  the  psoas  magnus,  and  are  inserted  along  with  it, 
or  rather  into  it ; the  inferior  fibres  are  also  inserted  into  the  anterior  and 
inner  surface  of  the  femur,  below  the  lesser  trochanter.  Use;  to  assist  the 
psoas  in  flexing  the  thigh,  and  in  rotating  it  outwards  ; it  also  abducts  it;  if 
protects  the  fore  part  of  the  capsular  ligament,  and  inflexion  of  the  thigh 
draws  it  out  of  the  angle  between  the  neck  of  the  femur  and  the  edge  of  the 
acetabulum. 

This  muscle  fills  up  the  concavity  of  the  iliac  fossa;  on  the  right  side  it  is 
covered  by  the  caecum,  on  the  left  by  the  colon ; in  the  groin  this  muscle  is 
partly  covered  by  the  sartorius,  and  it  lies  on  the  rectus  and  on  the  capsular 
ligament.  We  may  next  proceed  to  the  dissection  of  the  perinceum  and  the 
viscera  of  the  pelvis. 

§ 4. — Dissection  of  the  Perinseum  in  the  Male . 

Place  the  subject  on  the  back,  bend  the  thighs  and  knees  upon  the  trunk, 


OR  MANUAL  OF  ANATOMY. 


Ill 


and  secure  them  in  the  same  position  as  if  you  were  about  to  perform  the 
lateral  operation  of  lithotomy;  the  dissection  will  be  facilitated  if  the  pelvis 
be  raised  by  a block  placed  beneath  it ; moderately  distend  the  lower  end  of 
the  rectum  with  sponge  or  curled  hair;  introduce  a staff  or  catheter  into  the 
urethra  and  bladder;  secure  the  penis  to  it  by  a ligature,  and  raise  up  the 
scrotum.  The  perinaeum  extends  from  the  os  coccygis  behind,  to  the  arch  of 
the  pubis  before ; is  bounded  on  each  side  by  the  rami  of  the  pubis  and  ischium, 
by  the  tuber  ischii,  and  by  the  great  sacro-sciatic  ligament,  which  extends 
from  that  process  to  the  side  of  the  sacrum  and  coccyx ; the  glutasus  maximus 
overhangs  this  ligament ; the  tuberosity  and  ramus  of  the  ischium  can  be  felt 
through  the  integuments,  also  (unless  the  subject  be  very  fat)  the  ramus  of  the 
pubis  leading  obliquely  upwards  on  each  side  to  the  symphysis:  the  integu- 
ments of  the  perinaeum  and  scrotum  are  generally  of  a dark  brownish  color 
in  the  adult,  and  of  a reddish  hue  in  the  child;  very  thin  around  the  anus, 
and  covering  the  scrotum,  but  dense  in  the  intermediate  space : along  the 
mesial  line,  a prominent  hard  ridge  is  observable,  the  rciphe  of  the  perinaeum  ; 
this  line  commences  in  front  of  the  anus,  and  extends  along  the  perinaeum, 
scrotum  and  penis,  as  far  as  the  prepuce  of  the  latter.  Dissect  off  the  integu- 
ments from  this  region,  and  we  expose  posteriorly  a cutaneous  muscle  (the 
spincter  ani)  surrounding  the  anus,  and  anteriorly  a strong  fascia  covering 
the  muscles  of  the  perinaeum,  the  crura  penis,  and  the  corpus  spongiosum 
urethrae. 

Sphincter  Ani  is  flat,  thin,  oval,  pale,  and  open  in  the  middle;  it  arises 
from  a ligamentous  substance,  which  extends  from  the  os  coccygis  to  the  rec- 
tum; the  fibres  descend  obliquely  forwards,  expanding  on  either  side  nearly 
as  far  outwards  as  the  tuberosity  of  the  ischium ; at  the  posterior  part  of  the 
anus  this  muscle  divides  into  two  fasciculi,  which  pass,  one  at  each  side  of 
this  opening,  and  unite  at  its  anterior  part,  thus  encircling  this  orifice  ; inserted 
into  the  raphe  in  the  integuments,  and  into  the  superficial  fascia ; a fasciculus 
of  it  also  perforates  the  latter,  and  is  inserted  into  the  common  central  point 
of  the  perinaeum;  a point  which  will  be  more  fully  seen  when  the  fascia  shall 
have  been  raised.  Use ; to  close  the  anus;  it  may  also  draw  downward  the 
bulb  of  the  urethra ; this  muscle  is  almost  constantly  in  a state  of  contraction, 
and,  like  all  the  sphincter  muscles,  belongs  to  the  class  of  mixed  muscles. 
One  of  its  surfaces  looks  upwards,  the  other  downwards ; one  edge  is  internal, 
the  other  external.  It  is  superficial ; its  lateral  extent  is  much  greater  in 
some  subjects  than  in  others  ; a few  of  its  external  fibres  are  divided  in  the 
first  incision  in  the  lateral  operation  of  lithotomy; — beneath  and  internal  to 
this  muscle  we  may  expose  the  following,  with  very  little  dissection. 

Sphincter  Internus,  vel  Orbicularis,  consists  of  a thick,  but  pale  fasci- 
culus of  muscular  fibres,  which  encircles  the  lower  extremity  of  the  rectum, 
having  no  attachment  to  the  coccyx  behind,  and  but  a slight  one  to  the  central 
point  before : it  is  in  close  contact  with  the  mucous  membrane  of  the  intes- 
tine ; its  use  is  similar  to  that  of  the  last  described  muscle.  Its  surfaces  are 
internal  and  external,  its  edges  superior  and  inferior.  Anterior  to,  and  on 
each  side  of  the  anus,  we  find  beneath  the  integuments  a condensed  cellular 
texture,  covering  the  other  muscles  in  the  perinaeum  ; this  is  the  superficial 
fascia  ; it  is  continued  from  the  inner  side  of  one  thigh  across  the  perinaeum 
to  the  opposite,  adhering  to  the  rami  of  the  ischium  and  pubis  on  each  side. 


112 


THE  DUBLIN  DISSECTOR, 


by  tendinous  fibres;  this  fascia  is  very  dense  about  the  middle  of  the  peri- 
nseum ; posteriorly,  on  either  side  of  the  anus  it  is  loaded  with  soft  large 
grained  adipose  substance:  anteriorly  it  extends  over  the  scrotum,  and  be- 
comes thin  and  fine,  like  reticular  membrane,  and  continuous  with  the  super- 
ficial fascia  from  the  abdomen.  This  fascia  covers  the  vessels,  and  all  the 
muscles  of  the  perinaeum,  except  the  two  sphincters  of  the  anus.  Separate 
this  fascia  from  one  side  of  the  perinaeum,  and  reflect  it  towards  the  opposite  ; 
its  density  and  close  connection  to  the  lateral  boundaries  of  this  region  will 
then  become  obvious;  a number  of  veins  and  nerves,  and  a quantity  of  fat 
also  will  be  observed  ; when  the  latter  is  dissected  away,  those  muscles  of  the 
perinaeum,  which  are  attached  to  the  penis  and  urethra,  will  appear  covered, 
however,  by  a fine  but  dense  aponeurosis,  which  may  be  next  dissected  off: 
these  muscles  are  six  in  number,  three  on  each  side,  viz.  the  erector  penis, 
transversalis  perinaei,  and  accelerator  urinae*  If  the  perinaeum  be  divided 
by  a transverse  line  drawn  from  one  tuberosity  of  the  ischium  to  the  other, 
into  an  anterior  and  posterior  part,  we  shall  find  that  the  anterior  triangular 
space  contains  the  six  muscles  just  named,  also  the  crura  penis  and  the  corpus 
spongiosum  urethrae:  the  posterior  triangular  division  contains  the  lower 
extremity  of  the  rectum,  surrounded  by  the  cutaneous  and  deep  sphincters, 
also  on  each  side  of  this  intestine  a considerable  quantity  of  fat  filling  up  the 
space  between  the  side  of  the  rectum  and  the  obturator  internus  muscle  and 
fascia,  which  space  is  bounded  superiorly,  that  is,  separated  from  the  pelvis 
by  the  levator  ani  muscle,  and  interiorly  is  closed  by  the  fascia  and  integu- 
ments ; the  fat  is  from  two  to  three  inches  in  depth  ; when  this  mass  is  dis- 
sected out  of  the  space  which  it  fills,  the  levator  ani  muscle  will  be  seen  ex- 
tended from  the  internal  surface  of  the  pelvis  to  either  side  of  the  rectum, 
and  to  the  coccyx,  so  as  to  form  a partition  between  the  pelvis  and  the  peri- 
naeum. — First  examine  the  muscles  in  the  anterior  part  of  the  perinteum  ; the 
erector  or  compressor  penis  is  most  external,  and  lies  on  the  crus  penis  : the 
accelerator  urinae  extends  along  the  middle  of  the  perinaeum,  attached  to  its 
fellow  along  the  raphe,  and  covering  the  urethra ; the  transversalis  perinaei 
connects  the  posterior  extremities  of  these  muscles.  Immediately  in  front  of 
the  rectum,  in  the  middle  line,  and  behind,  but  connected  to  the  bulb  of  the 
urethra,  is  a small,  white,  tendinous  spot,  composed  of  condensed  cellular 
tendinous  substance  ; into  this  many  of  the  perinasal  muscles  are  inserted  ; it 
is,  therefore,  called  the  central  point  of  the  perinamm,  or  the  common  point  of 
insertion  to  the  muscles  of  the  perinaeum. 

Erector,  or  Compressor  Penis,  long  and  flat,  narrow  at  each  extremity, 
broader  in  the  middle,  arises  tendinous  and  fleshy  from  the  inner  surface  of 
the  tuber  ischii,  aud  from  the  insertion  of  the  great  or  inferior  sacro-sciatic 
ligament,  the  fibres  proceed  forwards,  upwards,  and  inwards,  adhering  to  the 
edges  of  the  rami  of  the  pubis  and  ischium,  and  covering  the  crus  penis.  The 
fleshy  fibres  terminate  in  a tendinous  expansion,  which  inclines  forw  ards,  up- 
wards, and  outwards,  and  is  inserted  into  the  fibrous  membrane  of  the  corpus 
cavernosum  or  crus  penis.  Use ; to  draw  down  the  penis  ; it  also  contributes 
to  the  erection  or  distension  of  this  organ  by  propelling  the  blood  into  it,  and 

* A knowledge  of  these  fascia:  will  explain  the  resistance  which  this  structure  presents 
to  collections  of  urine  or  of  pus  from  coming  to  the  surface. 


OR  MANUAL  OF  ANATOMY. 


113 


by  the  compression  of  the  veins  against  the  bone  preventing  the  free  return 
of  this  fluid  through  these  vessels. 

Accelerator  Urinje,  or  Ejaculator  Seminis,  is  in  the  middle  of  the  per- 
inaeum,  extends  from  the  front  of  the  rectum  to  the  back  part  of  the  scrotum, 
and  is  attached  to  its  fellow  along  the  mesial  line ; it  arises  first,  by  tendinous 
fibres  from  the  triangular  or  inter-osseous  ligament,  internal  to  the  erector 
penis  : secondly,  by  a broad  tendon,  which  is  common  to  the  opposite  muscle, 
and  which  lies  above  the  urethra,  between  it  and  the  pubis ; thirdly,  more  an- 
teriorly by  a tendinous  expansion  from  the  side  of  the  corpus  cavernosum 
penis.  The  posterior  and  middle  fibres  descend  inwards;  the  anterior  fibres, 
which  are  longer,  descend  obliquely  backwards  and  inwards;  all  the  fibres 
are  inserted  along  with  those  of  the  opposite  muscle  into  the  middle  tendinous 
line  or  raphe  of  the  perinseum,  which  extends  from  the  central  point  to  the 
back  of  the  scrotum. — Use;  to-expel  the  last  drops  of  urine  and  semen,  also 
to  distend  the  corpus  spongiosum  urethrae  by  propelling  the  blood  into  its  cells. 
The  posterior  origin  of  this  muscle  is  overlapped  by  the  erector  penis,  and  by 
the  perinaeal  vessels  and  nerves ; the  origin  of  the  middle  fibres  lies  above  the 
urethra,  and  that  of  the  anterior  is  external  to  the  crus  penis.  The  anterior 
fibres  of  this  pair  of  muscles,  by  converging  towards  the  middle  line,  resemble 
die  letter  Y.  The  acceleratores  urinae  muscles  fill  up  the  middle  of  the  per- 
inajum,  cover  the  bulb,  and  encircle  the  urethra  anterior  to  it.  Separate  these 
muscles  from  each  other  along  the  mesial  line,  and  detach  one  of  them  from 
the  corpus  spongiosum  urethrae;  then  by  examining  its  deep  surface, its  origin, 
particularly  that  which  lies  above  the  urethra,  anterior  to  the  bulb,  will  be 
more  distinctly  seen. 

Transversalis  Perin2ei,  is  thin  and  weak,  often  indistinct,  and  sometimes 
wanting;  it  arises  from  the  inside  of  the  tuberosity  of  the  ischium,  the  fibres 
pass  transversely  inwards  and  a little  downwards,  and  are  inserted  into  the 
central  point  of  the  perinseum,  behind  the  accelerator  urinae  muscle.  Use, 
to  fix  the  central  point,  and  support  the  anus  ; it  may  also  dilate  the  bulb. 
This  muscle  is  covered  by  the  sphincter  ani,  and  by  the  superficial  fascia,  a 
small  artery  (transversalis  perinaei)  runs  along  its  anterior  edge ; it  lies  on 
the  levator  ani,  is  connected  to  it  by  cellular  membrane,  and  in  some  cases  is 
intimately  joined  to  it.  In  some  subjects  a second  muscle  may  be  observed 
taking  a transverse  course  (the  transversalis  alter ) : this  arises  from  the 
ramus  of  the  ischium,  proceeds  obliquely  forwards  and  inwards,  and  is  in- 
serted into  the  accelerator  u rinse.  These  muscles  are  very  irregular  in  size  in 
different  persons,  in  some  being  found  very  distinct  and  strong,  in  others  a 
few  pale  and  scattered  fibres  only  point  out  their  course  and  situation.  Be- 
tween the  three  last  described  muscles  on  each  side,  we  may  remark  a trian- 
gular space,  which  is  bounded  externally  by  the  crus  penis  and  the  erector 
penis  muscle,  internally  by  the  urethra  and  accelerator  urinae ; the  base  is  pos- 
teriorly, and  is  formed  by  the  transversalis  perinaei  muscle.  This  space  con- 
tains a quantity  of  fat,  also  the  perinaeal  artery,  veins,  and  nerves,  branches  of 
the  pudic  vessels  and  nerves  ; into  this  space,  on  the  left  side  of  the  perinteum, 
the  operator  must  sink  his  knife  in  the  lateral  operation  of  lithotomy,  in  order 
to  lay  bare  the  groove  in  the  staff.  In  this  incision  the  transversalis  muscle 
and  artery  of  the  perinseum  must  be  divided.  Next  dissect  off  the  erector 
penis  from  the  crus  penis,  also  the  acceleratores  urinae  muscles  from  the  bulb 
15 


114 


THE  DUBLIN  DISSECTOR, 


and  corpus  spongiosum  urethrae;  detach  the  transverse  muscle  from  its  attach- 
ments, and  remove  the  vessels  and  cellular  membrane  out  of  the  triangular 
space  just  now  described ; then  press  the  bulb  of  the  urethra  to  one  side  from 
the  crus  penis,  and  between  these  two  bodies  we  may  observe  a strong  ligament- 
ous substance,  the  fibres  passing  in  different  directions ; this  is  the  triangular 
ligament  of  the  urethra  or  the  inter-osseous  ligament  of  the  perirueum.  The 
apex  of  this  ligament  is  above,  and  is  weak  and  cellular,  being  lost  in  front  of 
the  symphysis  pubis,  on  the  dorsal  vessels  of  the  penis ; the  sides  are  con- 
nected to  the  rami  of  the  pubis  and  ischium ; its  base  is  directed  towards  the  rec- 
tum, being  connected  in  the  middle  line  to  the  central  point  of  the  perinmum 
on  each  side  of  which  it  is  thin  and  weak,  and  gradually  lost  on  the  surface  of 
the  levator  ani.  Through  this  ligament  the  urethra  passesabout  an  inch  below 
the  inferior  edge  of  the  symphysis  pubis,  and  as  this  canal  passes  through  it, 
the  ligament  sends  a lamina  on  it  in  each  direction,  one  anteriorly  on  the  bulb 
the  other  posteriority  on  the  membranous  portion  of  the  urethra  and  prostate 
gland  ; the  former  is  called  the  anterior,  the  latter  the  posterior  layer  of  the 
triangular  ligament,  and  are  separated  from  each  other  bv  Cowper’s  glands 
and  the  artery  of  the  bulb.  The  anterior  layer  of  the  triangular  ligammt  is 
expanded  on  the  bulb,  and  gives  to  it  the  peculiar  glistening  appearance  it  now 
presents  ; it  also  retains  it  in  its  situation,  and  prevents  it  being  detached,  as 
will  appear  if  you  endeavor  to  draw  it  out  of  its  place.  The/iosferior  layer  is 
continued  backwards  around  the  membranous  part  of  the  urethra  to  the  pros- 
tate gland,  the  capsule  for  which  it  forms,  and  then  becomes  continuous  with 
the  reflections  of  the  pelvic  fascia  on  the  neck  of  the  bladder.  Divide  a few 
fibres  of  the  anterior  layer  of  this  ligament,  and  by  a little  dissection  you  will 
expose  on  eacli  side  of  the  bulb  a small  glandular  body,  Coieper's  or  the  anti- 
prostatic  glands  ; these  are  two  in  number,  about  the  size  of  a small  pea,  situated 
at  each  side  of,  and  behind  the  bulb,  below  the  membranous  part  of  the 
urethra,  between  the  layers  of  the  triangular  ligament,  and  closely  connected 
to  the  artery  of  the  bulb  ; they  are  covered  anteriorly  by  the  acceleratores 
urinse  muscles,  and  by  the  anterior  layer  of  the  triangular  ligament ; from  each 
a small  delicate  duct,  about  an  inch  in  length, passes  forwards,  opens  obliquely 
into  the  lower  and  lateral  part  of  the  urethra,  at  a little  distance  anterior  to 
the  bulb.  Dissect  away  all  the  cellular  membrane  at  the  side  of  the  rectum, 
between  it  and  the  tuber  ischii;  you  will  thus  expose  the  greater  portion  of  the 
levator  ani  muscle;  press  the  rectum  to  the  opposite  side,  and  you  will  then 
observe  how  this  muscle,  posteriorly,  and  the  triangular  ligament,  anteriorly, 
close  the  inferior  opening  of  the  pelvis,  and  separate  this  cavity  from  the  per- 
inasum.  Divide  the  triangular  ligament  on  one  side  from  the  rami  of  the  pubis 
and  ischium,  and  draw  it  over  towards  the  bulb  of  the  urethra,  which,  together 
with  the  rectum,  press  or  fasten  with  a tenaculum,  towards  the  opposite  tuber- 
osity of  the  ischium.  In  separating  this  ligament  from  the  bone,  the  pudic 
artery  and  its  terminating  branches  will  be  seen;  we  thus  also  expose  more 
fully  the  levator  ani  muscle. 

Levator  Ani,  flat,  thin  and  broad,  situated  at  the  inferior  part  of  the  pelvis, 
broader  above  at  its  origin  than  below  at  its  insertion  ; arises  fleshy  from  the 
posterior  part  of  the  symphysis  pubis  below  the  true  ligaments  of  the  bladder  : 
thin  and  tendinous  from  the  obturator  fascia,  and  from  the  ilium  above  the 
thyroid  hole ; thick,  tendinous,  and  fleshy  from  the  inner  surface  of  the  ischium , 


OR  MANUAL  OF  ANATOMY. 


115 


and  from  its  spinous  process  ; the  fibres  descend  obliquely  inwards,  by  the 
side  of  the  neck  of  the  bladder  and  rectum ; the  anterior  passing  more  back- 
wards than  the  others,  while  the  posterior  are  more  transverse  or  horizontal, 
inserted,  the  anterior  or  pubic  fibres  into  the  central  point  of  the  perinaeum, 
and  into  the  fore -part  of  the  rectum,  uniting  with  the  fibres  from  the  opposite 
side.  These  anterior  fibres  descend  along  the  side  of  the  prostate  gland  and 
the  membranous  part  of  the  urethra ; the  middle  fibres  into  the  side  of  the 
?'ectum,  passing  internal  to  the  sphincters,  and  united  to  the  outer  surface  of 
the  longitudinal  fibres  of  the  intestine  ; the  posterior  fibres  into  the  back  part 
of  the  rectum,  .and  into  a tendinous  raphe,  extending  from  it  to  the  os  coccygis, 
in  which  raphe  the  muscles  from  opposite  sides  unite,  also  into  the  two  last 
bones  of  the  coccyx.  Use,  to  raise  the  rectum  when  this  intestine  has  been 
protruded  by  the  efforts  of  the  abdominal  muscles  to  expel  its  contents;  it 
also  assists  in  closing  this  intestine,  it  compresses  the  vesiculae  seminales  and 
prostate  glar.d ; the  anterior  portion  supports  the  perinaeum  by  raising  the 
common  central  point,  and  may  also  compress  and  close,  like  a sphincter,  the 
membranous  portion  of  the  urethra;  the  levator  ani  completes  the  inferior 
boundary  of  the  pelvis  and  abdomen,  and  is  opposed  to  the  diaphragm  in 
respiration,  being  a muscle  of  expiration.  The  two  Ievatores  ani  muscles 
resemble  a funnel,  with  two  openings  in  it  inferiorly  : the  concavity  directed 
towards  the  pelvis,  the  convexity  to  the  perinseum;  through  the  anterior  aper- 
ture the  urethra  passes,  through  the  posterior  the  rectum.  On  the  perinaeal 
surface  of  this  muscle  are  placed  the  muscles,  the  triangular  ligament  and  the 
adipose  substance  of  which  we  have  spoken  ; the  pelvic  surface  of  this  muscle 
is  covered  by  the  peritonseum  and  by  the  pelvic  fascia,  which  cannot  be  seen 
in  the  present  dissection,  but  which  shall  be  noticed  presently.  At  the  ante- 
rior edge  of  each  levator  ani  muscle  fleshy  fibres  maybe  observed  to  surround 
the  membranous  part  of  the  urethra  very  closely.  These  fibres,  particularly 
at  their  insertion,  will  in  general  be  found  so  united  to  the  Ievatores  ani,  that 
they  may  be  considered  as  a portion  of  these  muscles  ; they  have,  however, 
been  described  by  Mr.  Wilson  as  a pair  of  distinct  muscles,  under  the  fol- 
lowing; names,  and  to  the  following;  effect : 

Compressor  Urethrae,  arises  by  a tendon  from  the  inside  of  the  symphysis 
pubis,  about  one-eighth  of  an  inch  above  the  lower  edge  of  the  arch,  and  at 
nearly  the  same  distance  beneath  the  anterior  ligaments  of  the  bladder,  to 
which,  and  to  the  tendon  of  the  opposite  muscle,  it  is  connected  by  loose 
cellular  membrane  ; thetendon  is  at  first  round,  but  becomes  flat  as  it  descends 
and  is  parallel  to  and  in  contact  with  its  fellow;  it  then  ends  in  fleshy  fibres, 
which  increase  in  breadth,  and  which,  approaching  the  upper  surface  of  the 
membranous  portion  of  the  urethra,  separate  from  those  of  the  opposite 
muscle,  descend  along  the  side  of  the  membranous  portion  of  the  urethra,  and 
folding  beneath  it,  again  Approach  the  muscle  of  the  opposite  side,  and  are 
inserted  with  it  into  a narrow  tendinous  line,  which  becomes  lost  in  the  common 
central  point  of  the  perinaeum.  Use,  to  compress,  contract,  close,  and  elevate 
the  membranous  portion  of  the  urethra ; these  fibres  encircle  the  narrowest 
partof  the  urethra,  that  portion  which  is  just  behind  the  bulb,  and  may,  by 
their  contraction  during  life,  form  such  an  impediment  to  the  passage  of  an 
instrument  into  the  bladder,  as  may  lead  the  surgeon  to  suspect  the  presence  of  a 
stricture,  when  in  reality  no  alteration  of  structure  exists.  The  origin  of  these 
muscles  are  occasionally  distinguished  from  the  Ievatores  ani,  by  some  small 


116 


THE  DUBLIN  DISSECTOR, 


veins  which  pass  from  the  side  of  the  neck  of  the  bladder  to  join  the  trunk  of 
the  dorsal  veins  of  the  penis,  but  their  insertion  is  confounded  with  these 
muscles  in  perinaso  behind  the  bulb. 

Let  the  student  next  replace  the  triangular  ligament,  &c.  and  then  re-con- 
sider  the  several  parts  before  him,  in  reference  to  the  operation  of  lithotomy : he 
has  already  examined  the  triangular  space  between  the  erector  penis  and 
accelerator  urinse  muscles,  into  which  the  knife  of  the  operator  is  to  sink  in 
order  to  reach  the  groove  in  the  staff;  this  space  has  been  fully  opened,  and  the 
staff  can  be  plainly  felt  or  seen  passing  above  the  bulb  through  the  membra- 
nous part  of  the  urethra  into  the  bladder:  behind  and  below  the  bulb  is  the 
rectum;  and  close  to  the  rami  of  the  pubis  and  ischium  are  the  internal  pudic 
vessels:  the  large  artery  from  the  pudic,  called  the  deep  transverse  artery, 
or  the  artery  of  the  bulb,  may  also  be  observed  passing  in  the  substance  of 
the  triangular  ligament,  about  an  inch  below  the  symphysis  pubis.  Hence 
then,  in  order  to  lay  bare  the  staff  without  injury  to  the  more  important  parts 
which  surround  it,  we  should  endeavour  to  open  the  urethra  as  near  to  the 
base  of  the  triangular  ligament  as  possible,  as  we  shall  thus  be  most  likely  to 
avoid  the  artery  of  the  bulb.  When  the  knife  of  the  operator  is  lodged  in  the 
groove  of  the  staff,  and  shall  then  be  pushed  along  it  into  the  bladder,  the  stu- 
dent will  now  perceive  that  the  posterior  layer  of  the  triangular  ligament,  the 
anterior  fibres  of  the  levator  ani*  and  the  left  lateral  lobe  of  the  prostate  gland 
must  be  divided  ; and  from  this  view  may  also  learn  that  the  rectum  will  be 
protected  from  injury  if  the  staff  be  well  raised  into  the  arch  of  the  pubes,  its 
groove  turned  a little  to  the  left  side,  and  the  wrist  of  the  operator  depressed, 
so  as  to  elevate  the  point  of  the  knife,  and  thus  direct  it  on  into  the  bladder; 
as  to  withdrawing  the  knife  the  student  may  now  learn  in  what  direction  this 
can  be  done  with  safety  and  effect,  and  what  parts  require  to  be  divided  ; it  is 
to  be  withdrawn  slowly  and  steadily  in  a direction  backwards  and  outwards 
nearly  parallel  to  the  line  of  the  cutaneous  incision,  the  edge  so  lateralized 
as  to  avoid  cutting  the  rectum  posteriorly,  or  the  pubic  artery  externally:  in 
this  part  of  the  operation  the  middle  fibres  of  the  levator  ani  must  be  divided, 
also  the  adipose  substance  on  its  perinmal  surface.  The  student  may  now 
withdraw  the  staff  from  the  bladder,  and  pass  it  again  and  again  along  the 
urethra  into  that  cavity  ; he  will  soon  perceive  how  apt  the  point  of  the  instru- 
ment is  to  descend  into  the  sinus  of  the  bulb,  and  the  necessity  of  depressing 
the  handle  of  the  staff,  in  order  to  raise  the  point  into  the  membranous  part  of 
the  urethra  ; at  the  same  time  he  should  observe,  that  the  latter  is  about  an 
inch  below  the  arch  of  the  pubes,  and  that,  therefore,  the  point  of  the  instru- 
ment is  not  to  be  too  much  elevated,  otherwise  it  may  lacerate  the  upper  part 
of  the  urethra,  and  injure  some  large  veins  that  may  be  found  in  this  situation. 
The  student  may  now  also  examine  what  occupies  the  space  between  the 
urethra  and  the  pubes ; immediately  above  that  canal  is  the  upper  portion 
of  the  triangular  ligament,  attached  to  the  crura  penis;  behind  this  ligament 
are  one  or  two  large  veins  from  the  dorsum  of  the  penis,  these  enter  the 
pelvis  along  the  upper  surface  of  the  prostate  gland  ; above  these  is  a 
smooth  dense  ligament,  the  pubic  ligament,  which  is  attached  to  the  lower 
edge  of  the  symphysis  pubis,  and  rounds  off  the  angle  between  the  opposite 
rami. 

Posterior  to  the  levator  ani  and  overlapped  by  the  glutaeus  maximus,  is  the 
following  small  muscle: 


OR  MANUAL  OF  ANATOMY. 


nr 


Coccygeus,  triangular,  at  the  inferior  and  posterior  part  of  the  pelvis,  be- 
hind and  above  the  levator  ani,  arises  narrow  from  the  inner  surface  of  the 
spine  of  the  ischium,  the  fibres  expand  along  the  inner  or  lesser  sacro-sciatic 
ligament,  and  are  inserted,  flesh  j and  tendinous,  into  the  extremity  of  the  sacrum 
and  side  of  the  coccyx:  Use,  to  support  the  os  coccygis  and  to  assist  in  closing 
the  inferior  and  posterior  parts  of  the  pelvis  ; this  muscle  is  between  the  leva- 
tor ani  and  the  glutaeus  maximus;  it  is  more  distinctly  seen  within  the  pelvis. 

Next  let  the  student  divide  the  central  point  of  the  perinseuin,  separate  the 
rectum  from  the  bulb,  and  draw  the  former  a little  downwards  from  the  bladder 
and  prostate  gland;  he  will  thus  expose  the  inferior  or  posterior  surface  of 
the  neck  of  the  bladder,  the  flat  posterior  surface  of  the  prostate  gland,  also  the 
vesiculae  seminales,  the  terminations  of  the  vasa  deferentia,  and  the  commenced 
ment  of  the  urethra,  but  the  most  important  part  to  direct  the  attention  to,  is 
a small  triangular  space  or  portion  of  the  bladder,  just  above  and  behind 
the  prostate  gland,  which  is  bounded  on  either  side  by  the  vasa  deferentia 
and  vesiculm  seminales  posteriorly  by  the  cul  de  sac  of  the  peritonaeum,  and 
anteriorly  by  the  prostate  gland  which  forms  the  apex  of  this  triangle  ; within 
this  space  the  muscular  coat  of  the  bladder  is  in  contact  with  the  rectum,  and. 
from  the  cavity  of  the  latter  the  former  organ  may  be  perforated  during  life 
■ without  injuring  any  important  part;  this  space  is  about  three  inches  and  a 
half,  or  four  inches  from  the  anus,  and  is  selected  by  some  surgeons  as  the 
best  situation  for  tapping  the  bladder  in  case  of  retention  of  urine,  when 
a catheter  cannot  be  passed  though  the  urethra.  The  student  may  now 
proceed  to  examine  the  pelvic  viscera;  for  this  purpose,  separate  the  left 
crus  penis  from  the  bone,  also  the  left  border  of  the  triangular  ligament 
(if  not  already  done),  and  detach  the  levator  ani  muscle  of  the  left  side  from 
the  bone  ; with  the  hand  separate  the  cellular  and  aponeurotic  bands  which  lie 
superior  to  this  muscle;  then  divide  the  symphysis  pubis,  or  saw  the  left  os 
pubis  about  half  an  inch  external  to  the  symphysis,  divide  the  left  ilio-sacral 
articulation,  cut  through  the  psoas  muscle  and  iliac  vessels,  and  then  remove 
the  os  innominatum  and  lower  extremity  of  the  left  side  ; the  pelvic  viscera 
will  remain  in  the  concavity  of  the  sacrum  and  of  the  opposite  os  innominatum. 
These  viscera  will  be  rendered  more  distinct  by  a little  dissection,  first, 
moderately  inflating  the  bladder  through  the  ureter,  a ligature  having  been 
tied  around  the  penis,  the  rectum  also  may  be  moderately  distended  with 
curled  hair  or  a sponge,  and  attached  to  the  spine  by  a ligature.  The  pelvic 
portion  of  the  peritonaeum  should  be  first  attended  to ; this  membrane  may  be 
now  seen  to  descend  along  the  sides  and  fore-part  of  the  rectum  to  within  about 
four  inches  of  the  anus,  whence  it  is  reflected  on  the  lower  and  back  part  of 
the  bladder;  the  line  of  this  reflection  is,  in  the  recumbent  position  of  the  sub- 
ject, opposite  the  lower  margin  of  the  third  piece  of  the  sacrum  ; in  the  erect 
posture  it  will  be  found  on  a level  with  the  junction  of  the  sacrum  and 
coccyx ; the  peritonaeum  is  reflected  on  the  bladder  between  the  middle  of  the 
vesiculas  seminales,  it  then  ascends  on  the  back  part  and  sides  of  this  organ  to  its 
superior  fundus,  whence  it  is  continued  to  the  abdominal  muscles ; below  the 
line  of  its  reflection  on  the  bladder,  or  below  the  cul  de  sac,  we  may  again 
fake  notice  of  the  triangular  space  on  the  inferior  fundas  of  the  bladder,  before 
alluded  to  as  the  situation  in  which  that  viscus  can  be  punctured  from  the 
rectum,  in  case  of  retention  of  urine.  The  reflections  of  the  peritonmum  from 


118 


THE  DUBLIN  DISSECTOR, 


each  side  of  the  rectum  to  the  back  part  of  the  bladder,  are  called  the  poste- 
rior ligaments,  and  the  fold  which  this  membrane  forms  on  each  side  between 
the  bladder  and  the  iliac  fossa  are  named  the  lateral  ligaments  of  the  bladder; 
these  shall  be  more  particularly  noticed  presently.  Remark,  the  curved  course 
of  the  rectum,  its  dilatation  near  the  anus,  also  the  connections  of  the  perito- 
naeum to  its  upper  and  middle  thirds,  and  observe  that  the  lower  third  of  this 
intestine  is  completely  below  and  unattached  to  this  membrane.  Next  study 
the  connections  of  the  urinary  bladder. 

Vesica  Urinaria,  when  contracted,  is  situated  in  the  anterior  and  inferior 
part  of  the  pelvis  behind  and  below  the  pubes ; when  distended  it  occupies 
more  or  less  of  the  hypogastric  region ; when  contracted,  it  appears  of  a flat- 
tened triangular  form,  the  base  towards  the  rectum,  the  apex  behind  the 
lower  edge  of  the  symphysis  pubis  ; when  distended,  it  presents  an  oval  figure, 
the  larger  end  towards  the  rectum,  the  smaller  and  anterior  end  towards  the 
recti  abdominis  muscles,  between  the  pubes  and  the  peritonaeum ; the  axis  of 
the  bladder  is  a line  directed  through  its  cavity  from  one  extremity  to  the 
other;  the  posterior  end  of  this  line,  if  produced,  would  touch  the  extremitv 
of  the  coccyx,  and  if  continued  anteriorly  it  would  reach  the  linea  alba,  mid- 
way between  the  pubes  and  the  umbilicus.  In  the  very  young  subject,  the 
bladder  is  of  a pyriform  figure,  and  is  principally  lodged  in  the  hypogastric 
region.  The  bladder  is  connected  to  the  parietes  and  to  the  viscera  of  the 
pelvis  by  folds  of  the  peritoneum,  and  by  the  reflections  of  the  pelvic  fascia. 
The  folds  of  the  peritoneum  are  termed  false  ligaments,  and  are  five  in  num- 
ber, viz.  two  posterior,  two  lateral,  and  one  superior:  the  true  ligaments  are 
reflections  of  the  pelvic  fascia,  and  are  four  in  number,  two  anterior  and  two 
lateral.  We  shall  first  consider  the  false  ligaments,  or  the  folds  of  the  peri- 
tonaeum, which  serve  to  connect  the  bladder  to  the  pelvic  viscera.  The 
posterior  ligaments  of  the  bladder  are  two  in  number,  one  on  each  side ; they 
lead  from  the  fore-part  of  the  rectum  to  the  back  part  of  the  bladder ; each  is 
of  a semilunar  form,  its  concavity  looking  forwards  and  upwards  ; in  this  fold 
are  contained  the  ureter  posteriorly,  and  the  obliterated  hypogastric  arterv 
anteriorly ; between  the  posterior  ligaments  the  cul  de  sac  of  the  peritonaeum 
descends.  This  membrane  will  be  also  found  thrown  into  one  or  two  semi- 
lunar folds  on  the  posterior  surface  of  the  bladder,  provided  this  viscus  be  in 
a state  of  contraction  ; these  disappear,  however,  when  it  becomes  distended; 
hence,  it  may  be  inferred,  that  these  folds  are  designed  to  admit  of  the  more 
easy  distension  of  this  organ.  The  lateral  ligaments  extend,  one  on  each  side, 
from  the  lateral  regions  of  the  bladder  to  the  iliac  fossae  ; each  contains  in  its 
duplicature  the  vas  deferens  in  the  male  subject,  and  the  ligamentum  teres  of 
•the  uterus  in  the  female.  The  superior  ligament  extends  from  the  summit  of 
the  bladder  to  the  recti  muscles  ; this  portion  of  the  peritonaeum  is  partial]  v 
reflected  over  the  remains  of  the  urachus  and  of  the  hypogastric  vessels 
Detach  the  peritonaeum  from  the  right  iliac  fossa,  and  gently  draw  the  bladder 
and  rectum  from  the  pelvis,  we  shall  then  observe,  that  the  neck  and  side  of 
the  former  are  retained  in  their  situation  by  the  reflection  of  a.  strong  fascia 
(the  pelvic  fascia)  from  the  parietes  of  the  pelvis  upon  this  viscus;  these 
reflections  are  the  true  ligaments  of  the  bladder.  The  pelvic  fascia  mav  be 
considered  as  a continuation  of  the  iliac  fascia  ; it  descends  from  behind  the 
iliac  vessels  and  from  the  brim  of  the  pelvis,  to  which  it  adheres,  and  lines 


OR  MANUAL  OF  ANATOMY. 


119 


the  parietes  of  the  cavity  as  low  down  as  the  upper  edge,  or  the  origin  of  the 
levator  ani  muscle  ; here  the  pelvic  fascia  divides  into  two  laminae,  between 
which  this  muscle  is  enclosed  r the  external  lamina  is  named  the  obturator 
fascia,  the  internal  the  vesical  fascia.  The  obturator  fascia  descends  between 
the  obturator  interims  and  levator  ani  muscles,  adhering  very  closely  to  the 
former,  and  is  inserted  interiorly  into  the  great  sciatic  ligament,  into  the  tuber 
ischii,  and  into  the  rami  of  the  ischium  and  pubis,  where  it  is  continuous  with 
the  triangular  ligament  of  the  urethra,  which  ligament  thus  appears  to  be  the 
continuation  of  the  obturator  fascia,  from  one  side  of  the  pelvis  to  the  other. 
The  vesical fascia  covers  and  adheres  to  the  internal  surface  of  the  levator  ani, 
lying  between  it  and  the  peritonaeum;  this  fascia  descends  anteriorly  to  the 
lower  edge  of  the  symphysis  pubis,  and  laterally  to  a level  with  a line  carried 
from  this  point  round  to  the  spine  of  the  ischium  ; from  the  pubes  it  is 
reflected  on  the  upper  surface  of  the  prostate  gland,  and  on  the  neck  of  the 
bladder,  forming  the  anterior  true  ligaments  of  this  organ;  laterally  it  is 
reflected  from  the  pelvis  on  the  side  of  the  prostate,  and  on  the  lower  part  of 
the  side  of  the  bladder,  just  above  the  outer  edge  of  each  vesicula  seminalis, 
and  thus  it  forms  the  true  lateral  ligaments  of  the  bladder;  posteriorly  the 
vesical  fascia  becomes  thin  and  cellular,  is  attached  to  the  side  of  the  rectum, 
and  lost  on  the  nerves  and  vessels  passing  into  and  out  of  the  pelvis.  The 
vesical  fascia  thus  forms  a pouch  on  each  side  of  the  bladder,  which  assists  in 
closing  the  pelvis;  it  also  fixes  the  pelvic  viscera,  supports  the  peritonaeum, 
and  resists  the  pressure  of  the  abdominal  muscles  and  diaphragm.  This  fascia 
is  perforated  by  several  blood-vessels. 

The  anterior  ligaments  of  the  bladder  are  two  in  number ; they  arise,  each, 
from  the  lower  margin  of  the  pubis  by  the  side  of  the  symphysis  ; pass  back- 
wards and  upwards  on  the  upper  surface  of  the  prostate  gland,  and  expand  on 
the  anterior  part  of  the  bladder;  many  of  their  fibres  may  be  seen  to  become 
continuous  with  the  muscular  fibres  of  the  bladder.  A depression  exists 
between  these  two  ligaments,  along  with  the  dorsal  veins  of  the  penis  pass 
from  beneath  the  arch  of  the  pubes  to  the  side  of  the  bladder  in  their  course  to 
the  internal  iliac  veins,  in  which  they  terminate ; the  pelvic  fascia,  however, 
is  not  deficient  between  these  ligaments,  but  is  continued  from  one  to  the 
other,  so  as  to  line  this  depression  and  cover  the  superior  surface  of  these 
veins.  The  true  lateral  ligaments  of  the  bladder  are,  one  on  each  side ; each 
is  continuous  with  the  anterior  ligament,  and  is  formed  by  the  reflection  of  the 
pelvic  fascia  from  the  inner  surface  of  the  levator  ani  to  the  side  of  the  pros- 
tate gland  and  of  the  bladder. 

The  superior  and  anterior  extremity  of  the  bladder  is  sometimes  named  the 
superior  fundus ; the  posterior  extremity,  which  presses  against  the  rectum, 
the  inferior  fundus;  the  intervening  portion  is  called  the  body, and  that  part 
which  is  connected  to  the  pubes  the  cervix;  the  latter  is  surrounded  by  the 
prostate  gland,  very  little,  however,  of  this  gland  being  above  it.  The  cervix 
presents  somewhat  a conical  figure;  and  in  the  adult  lies  nearly  horizontal, 
below  and  behind  the  pubes  ; in  the  child  it  is  more  vertical.  If  the  bladder 
be  moderately  distended  it  will  be  found  to  present  six  regions,  on  each  of 
which  some  important  object  may  be  noticed.  1st,  The  superior  region,  is  in 
contact  posteriorly  with  the  convolutions  of  the  small  intestines,  and  anteriorly 
with  the  recti  abdominis  muscles;  to  it  are  attached  the  urachus  and 


120 


THE  DUBLIN  DISSECTOR, 


obliterated  umbilical  arteries ; posterior  to  these  this  region  is  covered  by  the 
peritonmum,  whereas  anterior  to  them  this  membrane  is  deficient.  If  the 
bladder  be  much  distended,  this  region  is  sometimes  found  to  incline  to  the 
left  side.  2d  and  Sd,  The  lateral  regions,  are  contiguous  to  the  sides  of  the 
pelvis,  to  the  vesical  fascia,  and  to  the  levatores  ani  muscles ; descending 
obliquely  backwards  along  this  region  on  each  side,  we  find  the  vas  deferens 
crossing  over  the  obliterated  umbilical  artery  above,  and  over  the  ureter 
below,  thus  passing  internal  to  both,  or  nearer  to  the  mesial  line;  the  perito- 
naeum adheres  to  so  much  of  each  lateral  region  of  the  bladder  as  lies  posterior 
to  the  vas  deferens  while  that  portion  anterior  to  it  is  deficient  of  this  serous 
covering.  4th,  The  anterior  region  is  behind  the  recti  muscles,  the  pubes, 
the  pubic  ligament,  and  the  triangular  ligament  of  the  urethra;  all  this  region 
wants  the  peritoneal  covering;  towards  its  inferior  part  we  observe  the  an- 
terior ligaments  of  the  bladder,  between  them  the  dorsal  veins  of  the  penis, 
and  below  them  the  neck  of  the  bladder  surrounded  by  the  prostate  gland. 
5th,  The  posterior  region  is  contiguous  to  the  rectum  in  the  male,  to  the  ute- 
rus in  the  female,  and  in  either  sex  occasionally  to  the  convolutions  of  the 
small  intestines;  all  this  region  is  covered  by  peritonaeum.  6th,  The  inferior 
region,  in  the  female,  lies  on  the  ureters  and  on  the  vagina;  in  the  male,  on 
the  vesiculm  seminales,  the  intervening  cul  de  sac  of  peritonaeum,  the  rectum, 
and  the  prostate  gland;  the  superior  and  posterior  part  of  this  region  is 
covered  by  the  peritonaeum ; but  anterior  to  the  line  of  the  reflection  of  this 
membrane,  from  the  bladder  to  the  rectum,  is  the  triangular  portion  of  this 
region,  in  which  the  peritonaeum  is  deficient,  and  which  has  been  already 
attended  to,  as  the  situation  in  which  the  operation  of  tapping  the  bladder  from 
the  rectum  may  be  performed. 

The  coats  of  the  bladder  are  four,  viz.  1st,  the  serous,  or  peritonaeal ; 2d, 
the  muscular;  3d,  the  cellular;  4th,  the  mucous  : the  serous  is  but  a partial 
coat,  it  covers  all  the  posterior  surface,  the  posterior  part  of  the  upper  and 
lower  fundus;  also  the  posterior  part  of  each  side.  All  the  anterior  region, 
the  fore-part  of  the  sides,  and  of  the  upper  and  lower  regions,  are  therefore 
uncovered  by  peritonaeum ; when  the  bladder  is  distended  there  is  more  of 
this  organ  in  proportion  covered  by  this  membrane  than  in  its  contracted 
state.  The  peritonEeal  covering  of  the  bladder  is  very  dense,  it  may  be  easily 
dissected  off  the  following.  2d,  The  muscular  coat  consists  of  fibres  w hich 
are  stronger  and  redder  than  the  muscular  fibres  on  any  of  the  other  hollow 
viscera;  they  take  different  directions;  those  of  the  superficial  layer  run 
chiefly  in  a longitudinal  direction,  are  connected  anteriorly  and  inferiorly  to 
the  anterior  ligaments  of  the  bladder,  and  superiorl  y to  the  urachus,  posteriorly 
and  inferiorly  to  the  base  of  the  prostate  gland  ; these  fibres  are  stronger  on 
the  anterior  and  posterior  surfaces  than  on  the  sides  of  the  bladder:  on 
the  latter  regions  they  run  obliquely.  The  anterior  fibres,  from  having  a fixed 
attachment,  are  called  by  some  the  detrusor  urinse  muscle:  the  deep  fibres 
mostly  take  a circular  direction,  are  u'eak  superiorly,  but  strong  near  the 
cervix,  where  they  are  supposed  to  act  as  a sphincter  muscle;  these  circular 
fibres  which  have  received  this  name,  may  be  more  distinctly  seen  by  everting 
the  bladder,  and  dissecting  oft’  the  mucous  membrane  near  the  orifice  of  the 
urethra  behind  the  uvula.  At  the  anterior  part  of  the  inferior  region  there  is 
a compact  layer  of  white  dense  fibrous  substance,  into  which  the  muscular 


OR  MANUAL  OF  ANATOMY. 


121 


fibres  of  the  bladder  are  inserted,  but  which  itself  does  not  appear  to  be  mus- 
cular except  near  the  cervix;  this  structure  will  be  found  to  correspond  with 
a particular  region,  which  will  be  noticed  presently  in  the  interior  of  the  blad- 
der, and  which  is  called  the  trigone,  or  the  velum.  Beneath  the  muscular  is 
the  third,  or  the  cellular  coat ; it  invests  the  whole  organ,  is  very  elastic,  and 
seldom  contains  any  adipose  substance.  Open  the  bladder  by  a perpendicular 
incision  through  its  anterior  part;  and  the  fourth,  or  the  mucous  coat,  will  be 
observed ; this  is  pale,  and  thrown  into  many  folds,  particularly  if  the  bladder 
had  been  empty,  for  this  membrane  has  no  contractile  power;  through  it  the 
muscular  fibres  project,  presenting  the  reticulated  appearance,  and  very  fre- 
quently the  mucous  membrane  forms  pouches,  or  small  sacks,  between  these : 
interiorly  is  seen  the  orifice  of  the  urethra;  it  is  somewhat  of  a crescentic 
figure,  a small  tubercle  (the  uvula)  projecting  into  it  from  below' : posterior  to 
this  the  mucous  membrane  presents  a smooth  and  dense  appearance  through- 
out a small  triangular  space  called  the  velum  or  trigone;  at  the  posterior 
angles  of  this  space  the  orifice  of  each  ureter  may  be  observed,  the  line  ex- 
tending between  these  forms  the  base  of  this  triangle ; this  line  is  somewhat 
semilunar ; the  sides  of  the  trigone  are  defined  by  lines  drawn  from  each 
ureter  to  the  uvula;  each  is  from  an  inch  to  an  inch  and  a half  in  length; 
beneath  the  membrane  covering  each  of  these  lines  pale  muscular  fibres  may 
in  general  be  found ; these  have  been  named  by  Mr.  Bell,  the  muscles  of  the 
ureters,  who  describes  each  as  arising  from  the  vesical  extremity  of  the  ureter, 
and  thence  descending  obliquely  forwards  and  inwards,  to  be  inserted  by  a 
tendon  common  to  its  fellow  into  the  uvula.  The  use  which  he  assigns  to 
them  is,  to  restrain  the  termination  of  the  ureters,  and  preserve  the  obliquity 
of  the  passage  of  these  tubes  through  the  coats  of  the  bladder  when  it  is  con- 
tracted ; for,  says  he,  without  this  provision  the  urine  would  be  sent  retrogade 
into  the  ureters,  instead  of  forward  into  the  urethra.  These  lines,  however, 
seldom  present  this  structure  so  distinctly  as  has  been  described,  and  how  far 
their  supposed  use  is  correctly  ascribed  to  them  is  very  questionable.  The 
uvula  of  the  bladder  is  a small  eminence  at  the  apex  of  the  trigone,  much  bet- 
ter marked  in  some  than  in  others;  it  is  merely  a thickening  and  peculiar 
organization  of  the  sub-mucous  tissue;  it  is  nearly  opposite,  but  a little  an- 
terior to  the  third  or  middle  lobe  of  the  prostate  gland.  The  trigone  is  the 
most  sensible  and  vascular  part  of  the  bladder:  posterior  to  the  trigone  the 
bladder  is  frequently,  particularly  in  old  subjects,  dilated  into  a sort  of  pouch. 
In  the  female  the  trigone  is  smaller,  but  broader  in  proportion  than  in  the 
male,  and  the  uvula  is  less  distinct.  The  urethra  is  the  next  division  of  the 
urinary  organs  to  be  examined ; as  this  canal,  however,  in  the  male,  is  the 
common  passage  for  the  urine  and  seminal  fluid,  or  as  it  is  a part  both  of  the 
urinary  and  generative  organs,  we  shall  postpone  the  description  of  it  until 
we  have  considered  the  latter.  The  organs  of  generation  in  the  male  are  the 
testicles  and  their  appendices,  the  vesiculse  seminales,  the  prostate,  and  anti- 
prostatic glands,  (the  latter  have  been  already  examined,)  the  penis,  and  the 
urethra.  We  shall  describe  these  organs  in  the  following  order:  1st,  thfe 
testes,  with  their  coverings;  2d,  the  vasa  deferentia;  3d,  the  vesiculse  semi- 
nales ; 4th,  the  prostate  gland  ; 5th,  the  penis ; and  6th,  the  urethra. 


16 


122 


THE  DUBLIN  DISSECTOR, 


DISSECTION  OF  THE  ORGANS  OF  GENERATION  IN  THE  MALE. 

1st.  The  testes;  these  two  glands  are,  in  the  very  young  fcetus,  contained 
in  the  abdomen  beneath  each  kidney  ; a short  time,  however,  previous  to  birth, 
they  descend  into  that  situation  which  they  are  found  to  occupy  in  the  adult, 
and  are  surrounded  by  several  tunics,  viz.  the  scrotum,  dartos,  superficial 
fascia,  tunica  communis,  tunica  vaginalis,  and  tunica  albuginea. 

The  scrotum  is  a process  of  common  integument  continued  from  the  inner 
side  of  each  thigh,  and  from  the  perinseum  and  penis;  it  is  generally  of  a dark 
brown  color,  thinly  covered  with  hair,  and  very  rugged,  being  thrown  into 
numerous  rugae,  it  is  so  thin  that  the  small  sub-cutaneous  veins  and  sebaceous 
follicles  can  be  seen  through  it;  the  prominent  hard  ridge  or  raphe  is  con- 
tinued from  the  perinaeum  along  its  middle  line  as  far  as  the  penis.  The 
dartos  is  the  cellular  tissue  immediately  subjacent  to  the  skin,  it  usually  pre- 
sents a reddish  appearance,  a number  of  small  vessels  being  distributed 
through  it;  its  texture  is  very  loose,  and  is  readily  distended  in  emphysema 
or  in  anasarca ; it  never  contains  any  fat ; it  is  somewhat  more  dense  in  the 
mesial  line  than  at  either  side.  The  dartos  is  connected  to  the  rami  of  the 
pubis  and  ischium  of  each  side,  and  to  the  raphe  in  the  middle,  thence  it 
ascends  between  the  testes  to  the  urethra,  and  thus  assists  in  forming  the 
septum  scroti.  The  dartos  manifests  during  life  a degree  of  contractility 
above  that  which  the  cellular  tissue  enjoys  in  any  other  situation  ; it  has  there- 
fore been  considered  by  some  as  a cutaneous  muscle ; this  idea  is  probably 
incorrrect,  although  it  certainly  possesses  the  power  of  corrugating  the  skin, 
distinct  from  that  rolling  motion  of  the  testicle  produced  by  the  cremaster 
muscle;  posteriorly  the  dartos  frequently  appears  to  derive  a few  muscular 
fibres  from  the  sphincter  ani.  The  superficial  fascia  of  the  scrotum  is  con- 
tinued from  that  of  the  abdomen  around  each  spermatic  cord  and  testicle ; it 
is  thin  and  loose,  and  becomes  continuous  with  the  fascia  of  the  perinieum: 
as  this  fascia  envelopes  the  cord  and  testis  on  each  side,  it  assists  the  dartos 
in  forming  the  septum  scroti,  and  so  retains  each  testicle  at  its  own  side.  The 
tunica  communis  is  composed  of  the  expanded  fibres  of  the  cremaster  muscle 
and  of  fine  connecting  cellular  membrane  ; this  tunic  surrounds  the  cord  and 
testis;  the  fibres  of  the  cremaster  are  expanded  chiefly  on  the  fore-part  and 
sides  of  the  testis.  The  tunica  vaginalis  was  originally  a process  of  the 
peritonaeum,  having  been  prolonged  along  the  cord  and  around  the  testicle  as 
the  latter  was  descending  from  the  abdomen  to  the  scrotum ; at  this  early  age, 
the  tunica  vaginalis  in  the  scrotum  communicated  with  the  general  cavity  of 
the  peritonaeum  by  a sort  of  canal  which  led  along  the  fore-part  of  the  cord 
from  the  abdomen  to  the  scrotum:  this  canal,  however,  about  the  period  of 
birth  was  closed  by  adhesive  inflammation,  and  ever  afterwards  the  cavity  of 
the  tunica  vaginalis  is  quite  distinct  from  that  of  the  peritonaeum.  The  tunica 
vaginalis,  therefore,  is  a serous  membrane,  a shut  sac,  suspending,  and  partly 
enclosing  the  testicle,  and  also  reflected  over  its  anterior  part  and  sides  : that 
portion  of  it  which  suspends  the  gland,  and  which  lines  the  scrotum,  may  be 
named  the  tunica  vaginalis  scroti ; while  the  reflected  portion  which  covers 
the  sides  and  the  fore-part  of  the  testicle  is  the  tunica  vaginalis  testis.  This 
membrane  is  so  loosely  connected  to  the  scrotum  that  it  can  be  detached  form 


OR  MANUAL  OF  ANATOMY. 


123 


it  with  little  force;  it  is  thence  reflected  on  the  side  and  fore-part  of  the  epi- 
didymis and  testis ; it  also  ascends  a short  distance  on  the  fore-part  of  the 
cord ; the  posterior  part  of  the  epididymis  is  altogether  uncovered  by  it : as 
it  is  continued  from  the  epididymis  to  the  testicle  it  passes  in  between  these 
organs,  particularly  on  their  outer  side,  so  as  to  form  a sort  of  pouch  between 
them.  Both  the  testicle  and  epididymis  are  in  reality  behind  this  serous 
membrane,  and  nothing  is  contained  within  its  cavity  except  the  serous  fluid, 
which  lubricates  its  opposed  surfaces,  and  which  facilitates  that  gliding  motion 
which  the  testicle  undergoes  in  the  scrotum.  When  the  anterior  part  of  the 
tunica  vaginalis  is  divided,  we  see  its  internal  surface  smooth  and  polished, 
and  shining  through  its  reflected  layer  which  covers  the  testis,  we  can  discern 
the  next  tunic  of  this  gland,  tunica  albuginea : this  is  a dense  fibrous  mem- 
brane ; it  forms  the  proper  capsule  of  the  gland,  adheres  to  it,  preserves  its 
peculiar  form,  and  sends  several  processes  or  septa  into  the  testicle,  which 
will  be  seen  when  the  body  of  the  latter  shall  have  been  opened ; it  has  no 
connection  to  the  epididymis  : it  is  difficult  to  dissect  off  the  reflected  layer 
of  the  serous  membrane,  orthe  tunica  vaginalis  testis  from  the  tunica  albuginea 
they  are  so  intimately  united  ; through  the  latter  several  blood-vessels  can  be 
distinctly  seen.  Each  testicle  is  of  an  oval  form,  flattened  on  each  side,  also 
a little  on  the  back  part  beneath  the  epididymis  ; it  is  suspended  rather  ob- 
liquely, the  superior  extremity  being  directed  forwards  and  outwards,  the 
inferior  backwards  and  inwards.  Bent  like  an  arch,  along  the  posterior 
surface  of  each  testicle,  is  the  epididymis,  long  and  narrow,  large  above 
(globus  major),  narrow  in  the  middle  (body),  and  again  enlarged  below  (globus 
minor),  attached  to  the  testicle  above  by  vessels,  and  in  the  rest  of  its  extent 
by  the  reflected  layer  of  the  tunica  vaginalis,  closely  on  the  internal,  but  very 
loosely  on  the  external  or  femoral  side  ; from  its  inferior  extremity  the  vas 
deferens  proceeds,  and  thence  ascends  along  its  internal  side.  Divide  the 
tunica  albuginea  anteriorly  and  we  observe  the  testicle  to  be  composed  of  a 
soft  greyish  pulpy  substance,  which,  when  opened  out  a little,  and  floated  in 
water,  is  found  to  consist  of  numerous  fine  tortuous  shreds  or  vessels  of  deli- 
cate texture,  loosely  connected  to  each  other  ; some  are  of  considerable  length, 
and  with  a little  care  may  be  drawn  out  of  the  gland  to  the  extent  of  two  or 
three  feet ; they  are  placed  in  packets  or  fasciculi,  which  are  separated  from 
each  other  by  fibrous  bands  or  septa,  which  are  derived  from  the  tunica  albu- 
ginea, and  which  may  now  be  seen  to  pass  in  considerable  numbers  through 
the  gland  towards  the  back  part,  where  they  join  the  corpus  highmorianum : 
this  name  is  applied  to  a long  fold  or  process  of  the  tunica  albuginea,  which 
projects  into  the  back  part  of  the  gland;  it  consists  of  two  laminae,  between 
which  the  vessels  and  nerves  of  the  testicle  are  enclosed : this  process  is 
broader  above  than  below,  is  perforated  in  the  former  situation  by  the  excre- 
tory ducts  of  the  testicle ; to  its  anterior  border  and  sides  are  attached  the 
sepimenta  or  processes  of  the  tunica  albuginea  before  mentioned.  Erom  the 
several  collections  of  small  tubes,  which  are  disposed  between  these  bands  or 
septa,  about  twelve  or  twenty  larger  vessels  may  be  seen  to  proceed  nearly  in 
parallel  lines  towards  the  back  part  of  the  gland ; these  are  the  lubuli  recti ; 
they  pierce  the  corpus  highmorianum,  and  if  one  lamina  of  this  process  be 
raised  off  they  will  be  seen  entangled  with  each  other,  and  with  the  vessels 
and  nerves  of  the  gland:  this  structure  receives  the  name  of  Bets  Testriv, 


124 


THE  DUBLIN  DISSECTOR, 


which  is  therefore  placed  near  the  posterior  part  of  the  gland,  and  enclosed 
between  the  laminae  of  the  corpus  highmorianum;  from  the  upper  part  of  this 
tissue  five  or  six  tortuous  vessels  ascend  obliquely  backwards,  pierce  the 
tunica  albuginea,  and  arrive  at  the  head  of  the  epididymis ; here  they  increase 
in  size,  and  become  coiled  or  convoluted  ; these  are  the  vasa  efferenlia  or 
coni  vascu/osi : they  all  terminate  in  the  head  or  globus  major  of  the 
epididymis,  and  unite  into  one  small  duct  (the  vas  deferens),  which  is  twisted 
and  coiled  over  and  over  again  in  a most  extraordinary  and  peculiar  manner. 
The  body  and  globus  minor  of  the  epididymis  are  solely  composed  of  this 
convoluted  vessel,  which  by  care  may  be  unravelled  to  a great  extent;  the 
convolutions  of  this  tube,  of  which  the  epididymis  thus  consists,  are  con- 
nected to  each  other  by  fine  cellular  tissue  and  by  the  reflected  tunica  vaginalis; 
the  epididymis  has  no  fibrous  capsule  like  the  testis;  from  its  lower  extremity 
the  vas  deferens  at  length  escapes,  and  increasing  in  size  and  density,  this 
duct  bencls  upwards  along  the  inner  side  of  the  epididymis,  and  a little  above 
the  head  of  the  latter  it  becomes  connected  to  the  spermatic  vessels  and  cre- 
master muscle;  with  these  it  continues  its  course  obliquely  upwards  and  out- 
wards along  the  inguinal  channel,  and  through  the  internal  abdominal  ring: 
it  here  separates  from  the  spermatic  vessels,  the  latter  ascending  towards  the 
spine,  while  the  vas  deferens  passes  backwards,  inwards,  and  downwards, 
enclosed  in  the  lateral  fold  of  peritonaeum,  which  conducts  it  to  the  bladder, 
along  the  side  and  inferior  fundus  of  which  it  runs  internal  to  the  vesicula 
seminaris,  and  converging  to  its  fellow  ; at  the  base  of  the  prostate  gland 
each  vas  deferens  joins  the  duct  of  the  corresponding  vesicula,  and  the  union 
of  these  forms  the  ductus  ejaculatorius  communis , which  runs  through  the 
prostate  obliquely  forwards  and  inwards,  and  opeus  into  the  prostatic  portion 
of  the  urethra  on  the  side  of  the  verumontanum.  While  the  vas  deferens  is 
contained  in  the  spermatic  cord,  it  lies  posterior  to  the  spermatic  arteries  and 
veins,  and  to  the  cremaster  muscle  ; as  it  passes  through  the  internal  ring  it 
hooks  round  the  epigastric  artery,  being  separated  from  it  bv  the  spermatic 
artery  alone;  the  vas  deferens  next  passes  over  the  psoas  and  iliac  muscles, 
the  external  iliac  artery  and  vein  : it  then  bends  over  the  obliterated  hypo- 
gastric artery  and  descends  internal  to  it;  and  in  the  same  manner  it  next 
crosses  over  the  urethra,  so  as  to  lie  at  first  anterior  to  that  tube,  or  between 
it  and  the  bladder,  and  then  to  descend  along  its  internal  side;  the  vas  defer- 
ens then  runs  between  the  bladder  and  rectum,  near  to  its  fellow,  and  internal 
to  the  vesicula  seminalis,  as  far  as  the  prostate  gland,  which  it  perforates  in 
the  direction  before  mentioned.  This  vessel  has  a peculiar  hard  wiry  feel 
like  whip-cord : its  caliber  is  small  ; its  coats  are  two  in  number,  an  internal 
mucous,  and  an  external,  very  thick,  firm  and  white,  like  cartilage.  Between 
the  vesiculae  each  vas  deferens  is  flattened,  enlarged,  and  often  convoluted  : 
when  it  enters  the  prostate  it  again  contracts,  and  its  firm  external  tunic  ceases. 
In  some  a second  duct  will  be  found  to  leave  the  testis  and  to  run  for  some 
distance  parallel  to  the  vas  deferens,  which  in  some  cases  it  will  join,  while 
in  others  it  will  be  found  to  end  in  a cul  de  sac.  The  spermatic  cord  extends 
from  the  epididymis  to  the  internal  abdominal  ring;  it  consists  of  the  vas 
deferens,  spermatic  artery,  veins,  and  nerves  ; this  fasciculus  of  vessels  is 
covered  by  loose  cellular  membrane,  and  by  the  cremaster  muscle:  b.aeath 
the  latter  the  vessels  of  the  cord  will  be  found  joined  together  by  a fine  but 


OR  MANUAL  OF  ANATOMY. 


125 


tolerably  dense  membrane,  named  the  tunica  vaginalis  of  the  cord;  this  mem- 
brane is  the  remains  of  that  portion  of  peritonaeum  which  in  the  foetus  accom- 
panied the  spermatic  vessels  of  the  scrotum,  and  which  after  birth  lost  its 
serous  characters,  and  became  converted  into  condensed  cellular  membrane; 
this  covering  is  strengthened  by  that  prolongation  of  the  fascia  transversalis 
which  is  continued  from  the  internal  abdominal  ring  along  the  spermatic 
vessels. — The  spermatic  artery  arises  from  the  abdominal  aorta  below  the 
renal  artery,  and  not  unfrequently  from  the  latter ; it  descends  along  the  psoas 
muscle,  passes  through  the  internal  abdominal  ring  on  the  outer  side  of  the 
epigastric  artery;  it  then  enters  the  spermatic  cord,  and  is  conducted  to  the 
back  part  of  the  testicle;  it  divides  into  several  branches  which  enter  therete 
testis;  these  subdivide  minutely  as  they  proceed  into  the  substance  of  the 
testicle,  in  which  they  terminate  in  the  commencement  of  the  tubuli  seminiferi 
and  of  the  spermatic  veins.  The  last  named  vessels  leave  the  rete  testis, 
twine  around  the  arteries,  and  then  ascend  in  the  spermatic  cord  ; a little 
above  the  testicle  these  vessels  become  very  tortuous,  and  form  a plexus,  which 
is  named  the  Corpus  Pampiniforme  : the  spermatic  veins  then  accompany  the 
spermatic  artery  through  the  inguinal  canal  and  along  the  psoas  muscle  towards 
the  spine;  the  spermatic  vein  on  the  right  side  generally  ends  in  the  inferior 
cava  near  the  entrance  of  the  right  renal  vein  ; the  spermatic  vein  on  the  left 
side  frequently  ends  in  the  left  renal  vein.  The  nerves  of  the  testicle  are 
derived  chiefly  from  the  spermatic  plexus,  which  is  formed  by  the  union  of 
branches  from  the  lumbar  ganglions  of  the  sympathetic,  with  filaments  from 
the  splanchnic  nerves  and  from  the  renal  plexus ; the  cremaster  muscle  is  also 
supplied  by  branches  from  the  lumbar  plexus  of  spinal  nerves,  hence  this 
muscle  is,  to  a certain  extent,  voluntary. 

The  vesiculse  seminales  are  two  in  number ; they  are  situated  on  the  infe- 
rior surface  of  the  bladder  behind  and  above  the  prostate  gland,  on  the  outer 
side  of  the  vasa  deferentia,  and  anterior  to  the  rectum;  each  is  of  an  oval 
figure,  about  two  inches  long  and  half  an  inch  broad  ; the  superior  and  posterior 
extremity  is  round,  and  in  contact  with  the  ureter;  the  anterior  extremity  is 
narrow,  connected  to  the  prostate  gland,  and  ends  in  a small  duct  which  joins 
the  vas  deferens  ; the  union  of  these  forming  the  common  seminal  or  ejacula- 
tory duct,  which  latter  passes  obliquely  forwards  and  inwards  through  the 
prostate  gland,  and  opens  into  the  urethra  by  the  side  of  the  verumontanum. 
Although  the  vesiculse  look  like  a congeries  of  cells,  yet  by  dissection  they 
may  be  unravelled,  so  as  to  appear  as  one  continued  tube  convoluted  or  coiled 
very  much,  the  different  coils  communicating  with  each  other;  these  organs 
are  covered  by  a dense  fascia,  which  is  continued  from  that  covering  the  pros- 
tate gland.  Each  vesicula  consists  of  two  tunics,  viz.  mucous  membrane 
internally,  and  peculiar  gray  substance  externally,  somewhat  similar  to,  but 
softer  than  the  outer  coat  of  the  vas  deferens.  The  vas  deferens  communi- 
cates more  freely  with  the  corresponding  vesicula  than  the  latter  does  with  the 
former,  hence  air  or  fluid  injected  into  the  vas  deferens  will  generally  distend 
the  vesicula  seminalis  of  the  same  side  before  it  escapes  into  the  urethra.  These 
organs  are  generally  believed  to  contribute  some  additional  secretion  to  the 
seminal  fluid,  rather  than  to  serve  as  reservoirs  for  the  latter;  their  exact  use, 
however,  is  not  well  known  ; they  are  wanting  in  many  animals.  The  Pros- 
tate gland  is  situated  at  the  anterior  and  inferior  part  of  the  pelvis,  behind  the 


126 


THE  DUBLIN  DISSECTOR, 


triangular  ligament,  in  front  of  the  rectum,  to  which  it  is  connected  by  cellular 
membrane;  it  surrounds  the  neck  of  the  bladder,  and  is  attached  by  the  an- 
terior ligaments  of  this  organ  to  the  lower  edge  of  the  symphysis  pubis,  from 
which  it  is  about  three-fourths  of  an  inch  distant.  The  prostate  gland  is  some- 
what heart-shaped,  or  triangular;  it  is  also  compared  to  a chesnut ; the  base 
or  larger  extremity  is  posterior,  and  connected  to  vesiculae  seminales  ; the 
apex  is  anterior,  and  extends  within  a short  distance  of  the  triangular  ligament  ; 
the  neck  of  the  bladder,  and  about  an  inch  of  the  urethra,  run  through  its 
substance,  but  a small  portion  of  it  . lies  superior  to  the  neck  of  the  bladder 
and  urethra  ; this  part  is  convex,  and  is  covered  by  the  dorsal  veins  of  the 
penis,  and  by  the  anterior  ligaments  of  the  bladder ; the  inferior  or  posterior 
surface  of  the  gland  is  almost  flat,  a slight  groove  is  generally  observable  on 
it,  extending  along  the  mesial  line  ; this  surface  is  attached  to  the  fore-part 
of  the  rectum,  and  may  be  felt  distinctly  either  in  the  living  or  in  the  dead 
subject  by  the  finger  introduced  into  the  intestine  about  two  inches  and  a half 
above  the  anus;  the  sides  of  thegland  are  smooth  and  round,  and  are  covered 
by  a strong  fascia,  by  several  veins,  and  by  the  levatores  ani  muscles.  In  the 
base  or  posterior  end  is  a notch  for  the  entrance  of  the  common  ejaculatory 
ducts  ;J:his  notch,  together  with  the  groove  on  the  posterior  surface,  and  the 
passage  of  the  urethra  above  this,  have  caused  this  gland  to  be  described  as 
consisting  of  two  lateral  portions,  called  the  right  and  left  lateral  lobes ; these 
are  connected  to  each  other  posteriorly  by  a small  transverse  process,  called 
the  middle  lobe ; this  may  be  seen  by  detaching  the  vesiculae  seminales,  and 
vasa  deferentia  from  the  bladder,  and  leaving  them  suspended  by  their  com- 
mon ducts,  the  middle  lobe  of  the  prostate  will  then  be  seen  to  pass  from  one 
lateral  lobe  to  the  other,  and  to  be  closely  connected  to  the  mucous  membrane 
of  the  bladder. 

The  prostate  gland  has  a firm  resisting  feel,  is  of  a greyish  color,  and  ap- 
pears to  possess  a very  compact  structure  : this,  however,  is  chiefly  owing  to 
the  strong  fascia  which  invests  it,  and  which  forms  its  capsule : the  capsule 
has  been  already  described  as  being  partly  derived  from  the  posterior  layer 
of  the  triangular  ligament,  which  expands  on  the  sides  and  inferior  surface  of 
the  gland,  and  partly  from  the  reflection  of  the  pelvic  fascia  from  the  pubes, 
called  the  anterior  ligaments  of  the  bladder.  Next  continue  the  incision 
which  was  made  in  the  fore  part  of  the  bladder,  through  the  upper  part  of  the 
prostate,  so  as  to  lay  open  the  urethra,  we  shall  perceive  how  this  gland  sur- 
rounds the  canal,  also  the  greater  thickness  of  its  lateral  portions.  The 
prostate  glands  consist  of  several  follicles  or  acini  closely  connected  to  each 
other,  and  covered  externally  by  the  capsule,  and  internally  by  the  mucous 
membrane;  these  follicles  open  by  several  small  ducts,  ten  or  twelve,  on  the 
lower  surfaceof  the  urethra,  on  either  side  of  the  verumontanum  ; some  small 
ducts  also  open  on  the  upper  surface  of  the  canal. 

The  penis  is  covered  by  the  common  integuments,  and  by  the  superficial 
fascia;  the  skin  is  thin  and  loose;  it  is  continued  from  that  of  the  abdomen 
and  scrotum  around  this  organ,  and  extends  some  way  beyond  it  in  the  form 
of  a loose  fold,  the  prepuce;  from  the  extremity  of  this  process  the  skin  is 
reflected  inwards  as  far  as  the  corona  glandis,  where  it  becomes  very  thin ; it 
is  thence  continued  over  the  glans  penis  to  the  orifice  of  the  urethra  where  it 
as  continuous  with  the  lining  membrane  of  the  urethra ; inferior  to  this  opening 


OR  MANUAL  OF  ANATOMY. 


127 


it  forms  a fold,  the  fraenum  preputii ; the  prepuce,  therefore,  is  only  a fold 
of  the  common  integument,  the  sides  of  which  are  connected  together  by  very 
loose  cellular  tissue;  this  fold  is  expanded  when  the  prepuce  is  drawn  back, 
or  wlien  the  penis  becomes  distended : the  inner  side  of  the  prepuce  is  of 
more  delicate  texture  than  the  external,  and  that  portion  of  it  which  is  con- 
tinued over  the  glans  is  still  more  delicate  than  either.  Beneath  the  skin, 
around  the  corona  glandis,  are  a number  of  small  sebaceous  glands,  glandulae 
odoriferae  or  Tysoni.  The  superficial  fascia  which  covers  the  penis  is  con- 
tinued from  that  of  the  abdomen,  and  extends  around  the  penis  as  far  as  the 
corona  glandis;  it  is  thick  and  strong  posteriorly,  where  it  is  reflected  from 
the  linea  alba  on  the  penis,  so  as  to  form  the  superficial  suspensory  ligament 
of  the  latter ; anteriorly  it  is  loose  and  delicate.  Beneath  these  coverings 
the  penis  is  found  to  consist  of  two  long  cylindrical  bodies,  termed  the  crura 
or  corpora  cavernosa  penis  ; each  of  these  is  composed  of  a strong,  elastic, 
tendinous,  and  fibrous  substance,  forming  a sort  of  tube,  which  is  filled  with 
a soft  cellular  tissue,  through  which  a considerable  artery,  and  several  small 
tortuous  veins,  run  from  one  end  to  the  other.  Each  crus  penis  commences 
narrow  in  front  of  the  tuber  ischii,  and  adheres  to  the  rami  of  the  ischium  and 
pubis,  as  far  forwards  as  the  symphysis ; anterior  to  this  the  two  crura  become 
inseparably  united,  and  continue  so  as  far  as  the  corona  glandis ; here  each  crus 
ends  in  an  obtuse  point,  over  which  the  glans  penis,  which  is  the  expanded 
extremity  of  the  corpus  spongiosum  urethrae,  is  folded;  the  two  crura  are 
attached  to  the  symphysis  pubis  by  the  true  suspensory  ligament , which  is  very 
strong,  and  of  a triangular  figure ; it  arises  from  the  symphysis,  and  is  in- 
serted into  each  crus ; it  consists  of  two  laminae,  between  which  the  dorsal 
vessels  and  nerves  of  the  penis  pass.  The  crura  penis  are  separated  from 
each  other  by  an  imperfect  tendinous  septum,  composed  of  parallel  fibres, 
with  such  intervals  between  them  that  the  cavity  of  one  crus  communicates 
with,  and  can  be  injected  from  that  of  the  other ; this  septum  is  named  pecti- 
niforme.  The  crura  penis  are  somewhat  conical,  the  apex  of  each  being 
attached  to  the  ischium  and  pubis,  the  base  supporting  the  glans;  they  are 
round  externally,  flattened  towards  each  other ; a wide  and  deep  groove  exists 
between  them  inferiorly,  which  contains  the  urethra,  and  a more  superficial 
one  superiorly,  in  which  the  dorsal  vessels  and  nerves  of  the  penis  run.  The 
erection  of  the  penis  during  life  is  caused  by  a greater  quantity  of  blood  than 
usually  circulates  through  this  organ  being  propelled  by  an  increased  action 
of  the  arteries  into  the  small  vessels  of  the  corpora  cavernosa  penis : anato- 
mists are  not  agreed  as  to  the  exact  structure  of  the  corpora  cavernosa,  or  as 
to  the  proximate  cause  of  their  erection  during  life,  or  how  the  blood  is  cir- 
cumstanced during  that  condition ; some  consider  that  the  arteries  pour  then- 
blood  into  the  cells  of  the  cellular  tissue  which  surrounds  them,  so  as  to  cause 
their  distension,  and  that  from  these  the  blood  is  slowly  and  gradually  ab- 
sorbed by  the  veins;  others  conceive  that  the  arteries  directly  communicate 
with  the  veins,  and  that  these  latter  vessels  are  tortuous  and  coiled  to  such  a 
degree  as  to  retard  the  course  of  the  return  of  the  blood,  and  so  cause  the 
distension  and  consequent  erection  of  the  whole  organ. 

The  urethra  extends  from  the  neck  of  the  bladder  to  the  extremity  of  the 
penis  ; it  is  lined  by  a fine  mucous  membrane,  which  is  continuous  posteriorly 
with  the  mucous  membrane  of  the  bladder,  and  anteriorly  with  the  thin 


128 


THE  DUBLIN  DISSECTOR, 


integument)  which  is  reflected  from  the  inside  of  the  prepuce,  over  the  glans 
penis,  as  far  as,  and  even  within,  the  orifice  of  the  urethra.  This  membrane 
is  covered  at  first  by  the  prostate  gland,  and  this  portion  of  the  canal  is  called 
the  prostatic  portion  of  the  urethra ; the  next  succeeding  portion  is  covered  by 
the  compressores  urethrae  muscles,  by  the  triangular  ligament,  and  by  a pecu- 
liar reddish  or  spongy  looking  cellular  tissue,  which  contains  several  small 
blood-vessels,  chiefly  veins ; this  part  of'the  urethra  is  called  the  membranous 
portion ; the  remainder  of  the  canal  is  covered  by  a cellular  and  vascular 
substance  of  a dark  red  or  purple  color,  named  the  corpus  spongiosum  ure- 
thrae, which  commences  in  the  bulb,  and  ends  in  the  glans  penis;  this  portion 
of  the  urethra  is  named  the  spongy  portion.  The  first,  or  the  prostatic  por- 
tion of  the  urethra  is  within  the  pelvis;  it  is  about  an  inch  and  a quarter,  or 
an  inch  and  a half  in  length;  in  the  erect  position  of  the  body  its  direction  is 
downwards  and  forwards;  it  is  nearer  to  the  upper  than  to  the  lower  surface 
of  the  gland.  The  membranous  portion  is  about  half  an  inch  long;  it  is 
described  in  general  as  being  concave  towards  the  pubes : it  is,  however,  but 
very  slightly  so,  it  runs  nearly  horizontal,  about  three  quarters  of  an  inch 
below  the  symphysis  pubes.  The  spongy  portion  commences  in  the  bulb  in 
front  of  the  triangular  ligament,  extends  to  the  extremity  of  the  canal,  and 
ends  in  the  glans  penis;  this  part  of  the  canal  is  surrounded  by  a vascular 
and  cellular  texture,  named  the  corpus  spongiosum  urethrae,  which  has  some 
resemblance  to  the  corpora  cavernosa  penis.  The  corpus  spongiosum  urethra?, 
consists  of  a number  of  fine  cells,  which  communicate  with  each  other; 
through  these  an  artery  from  each  side,  (a  branch  from  the  internal  pudic) 
extends;  these  vessels  send  oft’  numerous  branches,  which  pour  their  blood 
into  the  surrounding  cells,  from  which  the  veins  afterwards  absorb  it : the 
bulb  and  the  glans  penis  are  expansions  of  this  cellular  texture,  the  former 
on  the  inferior,  the  latter  on  the  superior  part  and  sides. 

This  spongy  substance  is  invested  by  a fine,  but  strong  and  semi-transpa- 
rent aponeurosis  very  different  from  that  which  covers  the  corpora  cavernosa. 
The  corpus  spongiosum  surrounds  the  urethra,  but  is  thicker  interiorly  and 
laterally  than  superiorly;  there  is  no  direct  communication  between  the 
corpus  spongiosum  urethrae  and  the  corpora  cavernosa  penis,  the  one  can 
therefore  be  distended  with  air  or  injection  without  the  other,  or  both  may  be 
injected  with  different  colored  fluids.  In  order  to  inject  the  crura  penis, 
make  a small  opening  in  each  crus  near  its  attachment  to  the  ischium,  insert 
a pipe  into  one  of  these,  and  force  warm  water  through  it;  this  will  soon 
escape  through  the  opening  in  the  opposite  crus,  carrying  along  with  it  the 
blood  which  was  contained  in  the  cells,  then  secure  with  a ligature  the  oppo- 
site crus,  and  inject  some  colored  fluid.  To  prepare  the  corpus  spongiosum 
urethra,  make  a small  opening  in  the  substance  of  the  bulb,  next,  open  the 
dorsal  vein  of  the  penis,  in  it  secure  a small  pipe,  water  injected  through  this 
will  escape  at  the  opening  in  the  bulb;  when  all  the  blood  shall  have  been 
thus  washed  out,  the  latter  opening  may  be  secured,  and  some  colored  fluid 
injected  along  the  dorsal  vein. 

If,  however,  a fine  injection  be  forced  from  the  pudic,  or  from  the  internal 
iliac  artery,  it  may  be  made  to  distend  the  corpora  cavernosa  penis,  and  the 
corpus  spongiosum  urethra  at  one  and  the  same  time.  The  student  may  now 
detach  the  crura  penis  and  the  neck  of  the  bladder  from  the  pubes,  and 


OR  MANUAL  OF  ANATOMY. 


129 


remove  these  organs  together  with  the  urethra  from  the  subject ; continue  an 
incision  from  the  anterior  part  of  the  bladder  through  the  upper  part  of  the 
prostate  gland,  and  of  the  urethra  to  its  extremity;  the  mucous  lining  of  the 
urethra  will  be  thus  exposed,  the  difference  in  the  diameter  and  other  pecu- 
liarities in  different  parts  of  it  may  now  also  be  observed.  1st,  the  prostatic 
portion  is  somewhat  contracted  at  either  extremity,  and  dilated  in  the  centre, 
particularly  on  the  lower  surface,  and  at  either  side  of  the  middle  line ; these 
enlargements  are  called  the  prostatic  sinuses ; they  are  separated  from  each 
other  by  a prominent  fold  of  the  lining  membrane,  extending  from  the  uvula 
of  the  bladder  along  the  mesial  line  of  the  urethra,  as  far  as  the  bulb;  this 
fold  is  named  verumontanum,  or  caput  gallinaginis;  in  the  centre  of  it  is  a 
.very  large  lacuna  (sinus  pocularis),  the  orifice  of  which  is  directed  forwards  ; 
on  either  side  of  this  pouch,  and  in  general  external  to  it,  is  the  opening  of 
the  common  ejaculatory  duct,  external  to  which,  and  in  the  prostatic  sinus  on 
each  side  are  the  several  small  orifices  of  the  ducts  of  the  prostate  gland. 
2d,  the  membranous  portion  is  shorter,  and  of  a smaller  caliber  than  the  pros- 
tatic ; it  is  cylindrical,  its  anterior  extremity  is  the  narrowest  portion  of  the 
canal.  3d,  the  spongy  portion  of  the  urethra  is  much  dilated  at  first,  parti- 
cularly inferiorly  (sinus  of  the  bulb) ; anterior  to  this  the  small  ducts  of  the 
anti-prostatic  glands  open.  The  canal  of  the  urethra  contracts  a little  be- 
yond the  bulb,  and  continues  of  nearly  the  same  diameter  until  it  arrives 
opposite  the  scrotum ; it  is  there  slightly  contracted  for  a short  distance : 
about  an  inch  posterior  to  the  external  orifice  of  the  urethra  the  canal  is  dilated 
in  the  transverse  direction  ; this  dilation  is  called  fossa  navicularis : lastly, 
the  orifice  of  the  urethra  is  contracted  into  a narrow  vertical  slit.  Several 
small  lacunae  open  on  the  surface  of  the  mucous  membrane  of  the  urethra, 
between  the  bulb  and  the  anterior  extremity ; the  orifices  of  these,  in  a healthy 
condition  of  the  membrane,  are  very  small;  they  are  all  directed  forwards : 
if  bristles  be  introduced  into  some  of  these  ducts  they  will  be  found  in  many 
cases  to  extend  backwards  for  near  an  inch  in  the  submucous  tissue;  these 
lacunae  secrete  a thin  mucous  fluid,  which  is  expelled  by  the  urine  in  its  pas- 
sage along  the  urethra : in  chronic  diseases  of  the  urethra  these  ducts  not 
unfrequently  become  so  much  enlarged  as  to  admit  the  end  of  a small  bougie, 
and  so  lead  to  the  formation  of  a false  passage  : the  largest  lacunae  are  on  the 
upper  surface  of  the  urethra;  one  in  particular,  near  the  fossa  navicularis,  is 
named  the  lacuna  magna.* 

* During  the  dissection  of  the  pelvic  viscera,  perinseum,  &c.  the  student  should  fre- 
quently practice  the  introduction  of  a catheter  into  the  bladder,  which  is  to  be  done  in 
the  following  manner  : the  subject  lying  on  its  back  with  the  legs  drawn  up,  the  penis 
should  be  held,  by  placing  the  thumb  and  index  finger  on  each  side  of  the  corona  glandis, 
by  which  means  the  orifice  of  the  urethra  will  not  be  compressed  ; the  penis  is  then  to 
be  drawn  upwards,  and  the  catheter,  being  previously  oiled,  is  now  to  be  introduced  in  a 
line  with  the  linea  alba  into  the  urethra,  directly  downward  as  far  as  the  bulb  ; the  con- 
cavity of  the  instrument  being  towards  the  abdomen.  The  catheter  having  reached  the 
bulb,  its  handle  is  to  be  depressed  by  bringing  it  forwards  between  tire  thighs,  and  in 
proportion  as  this  is  done,  the  point  is  elevated,  and  the  catheter  glides  into  the  bladder  ; 
in  this  latter  part  of  the  operation,  the  penis  must  be  allowed  to  sink  down,  for  if  it  be 
kept  extended  on  the  instrument,  the  membranous  part  of  the  urethra  would  be  drawn 
towards  the  pubes,  by  which  means  the  introduction  of  the  instrument  would  be  rendered 
difficult. 


17 


ISO 


THE  DUBLIN  DISSECTOR, 


CHAPTER  VII. 

§ 1 . — Dissection  of  the  Female  Organs  of  Generation. 

The  generative  organs  in  the  female  are  more  distinct  from  the  urinary  than 
in  the  male  subject;  they  may  be  divided  into  the  external  and  internal : the 
external  parts  are  the  mons  veneris,  vulva,  labia,  clitoris,  nymphae,  vagina, 
and  perinaeum.  The  mons  veneris  is  an  eminence  placed  on  the  upper  and 
anterior  part  of  the  pubes;  it  consists  of  a quantity  of  adipose  substance  be- 
neath the  integuments,  which  in  the  adult  are  covered  with  hair.  The  vulva 
is  the  fissure  which  extends  from  the  mons  veneris  to  within  an  inch  of  the 
anus.  The  perinseum  is  the  small  space  in  front  of  the  anus.  The  labia  are 
the  thick  folds  of  integument  which  extend  one  on  each  side  of  the  vulva,  and 
are  united  inferiorly  in  a crescentic  edge,  called  the  pommissureor  fourchette. 
The  clitoris  is  between  the  superior  extremity  of  the  labia;  it  is  a small  red 
projection  immediately  beneath  the  symphysis  pubis  and  above  the  vagina ; 
it  is  attached  by  two  crura  to  the  rami  of  the  pubes ; these  unite  and  form  the 
body  of  the  clitoris,  on  the  anterior  extremity  of  which  is  a round  red  swell- 
ing called  the  glans  clitoridis;  this  is  covered  by  a thin  loose  fold  of  integu- 
ment called  the  prepuce.  The  clitoris  is  composed  internally  of  a spongy 
cellular  texture,  not  very  unlike  the  corpus  spongiosum  urethrae  in  the  male 
subject.  The  nymphse,  or  labia  minora,  descend  one  on  each  side  from  the 
prepuce  of  the  clitoris,  and  are  gradually  lost  about  the  centre  of  the  vulva. 
About  half  an  inch  before  the  clitoris  is  the  round  orifice  of  the  meatus  urina- 
rius;  this  opening  is  surrounded  by  a fold  of  mucous  membrane.  The  meatus 
is  from  an  inch  and  a half  to  two  inches  in  length;  it  leads  backwards  and 
upwards  along  the  upper  surface  of  the  vagina,  and  is  slightly  curved  beneath 
the  symphysis  pubis.  The  vagina  is  directly  below  the  urethra;  in  the  child 
it  is  partially  closed  in  front  by  a crescentic  fold  of  membrane,  termed  the 
hymen:  in  the  adult  several  reddish  eminences  surround  this  opening;  the 
course  and  connections  of  this  canal  will  be  better  seen  when  the  pelvis  shall 
have  been  divided  for  the  purpose  of  examining  the  internal  organs  of  gene- 
ration. Dissect  oft' the  integuments  and  fascia  from  the  perinseum  and  labia, 
and  the  following  muscles  maybe  seen:  the  sphincter  ani,  levator  ani,  and 
coccygaeus ; these  are  similar  to  the  muscles  of  the  same  name  in  the  male 
perinseum,  also  the  transversalis  perinasi : the  erector  clitoridis  is  analogous 
to  the  compressor  penis  ; and  the  sphincter  vaginae  corresponds  to  the  accele- 
rators urinae  ; it  extends  from  the  clitoris  superiorly  around  each  side  of  the 
vagina  to  the  central  point  of  the  perinseum  in  front  of  the  anus.  To  examine 
the  internal  organs  of  generation  make  a lateral  section  of  the  pelvis  in  the 
same  manner  as  was  directed  in  the  dissection  of  the  male  pelvis.  The  peri- 
tonaeum may  be  first  examined ; this  will  be  seen  to  descend  along  the  fore- 
part of  the  rectum,  to  within  three  or  four  inches  of  the  anus;  it  is  thence 
reflected  forwards  on  the  posterior  part  of  the  vagina,  the  superior  third  of 
which  it  covers  ; from  the  vagina  it  ascends  on  the  posterior  surface  and  sides 
of  the  uterus,  continues  round  the  superior  fundus  of  this  organ  to  its  anterior 
part,  on  which  it  descends  as  low  as  the  commencement  of  the  vagina;  it  is 
thence  reflected  to  the  bladder,  and  is  continued  over  this  organ,  as  in  the 
male  subject,  to  the  abdominal  muscles;  thus,  in  the  female,  pelvis  the 


OR  manual  of  anatomy. 


131 


peritonaeum  forms  one  cul  de  sac  between  the  rectum  and  vagina,  and  another 
between  the  uterus  and  bladder.  From  each  side  of  the  uterus  a broad  fold 
of  peritonaeum  is  extended  transversely  towards  each  iliac  fossa;  these  folds 
are  the  broad  ligaments  of  the  uterus;  enclosed  between  the  laminae  of  each 
of  these  are  the  Fallopian  tube,  the  round  ligament  of  the  uterus,  and  the 
ovarium  with  its  ligament  and  vessels.  Dissect  off  the  peritonaeum  from 
one  side  of  the  rectum  and  vagina,  and  the  pelvic  viscera  will  be  more  dis- 
tinctly seen ; the  rectum  takes  the  same  course  as  in  the  male,  only  somewhat 
more  curved.  The  vagina  is  seen  to  surround  the  neck  of  the  uterus,  and 
thence  to  descend  obliquely  downwards  and  forwards  between  the  rectum, 
the  bladder,  and  urethra;  closely  connected  to  the  latter,  and  but  loosely  to 
the  rectum.  The  vagina  is  lined  by  a vascular  membrane,  which  is  covered 
externally  by  a dense  fibrous  tissue  and  by  numerous  vessels,  particularly 
veins,  which  form  a plexus  (retiform)  or  spongy  body,  which  is  situated  be- 
neath the  sphincter  vaginae  muscle;  the  vagina  is  also  partially  covered  by 
peritonaeum  on  its  posterior  surface:  between  the  bladder  and  vagina  the 
ureter  may  be  observed;  its  course  is  longer  and  more  curved  in  the  female 
pelvis  than  in  the  male.  The  uterus  is  situated  between  the  bladder  and 
rectum,  and  connected  to  both  by  peritonaeum  ; the  broad  ligament  which  is 
a fold  of  peritonaeum,  and  the  round  ligament  which  is  a fasciculus  of  blood- 
vessels and  nerves  bound  together  by  dense  cellular  tissue,  connect  each  side 
of  this  organ  to  the  pelvis,  and  to  the  inguinal  region.  The  uterus  is  some- 
what pyriform  or  triangular,  the  larger  end  or  fundus  being  superiorly  and 
posteriorly,  the  smaller  end  or  cervix  interiorly  and  anteriorly ; the  inter- 
mediate portion  is  named  the  body ; the  vagina  surrounds  the  cervix  uteri, 
and  ascends  higher  posteriorly  than  anteriorly;  at  the  lower  extremity  of  the 
cervix  is  a small  transverse  slit,  termed  the  os  uteri  or  os  tineas.  The  uterus 
consists  of  a dense  fibrous  substance,  covered  externally  by  peritonaeum,  and 
lined  throughout  by  mucous  membrane,  which  is  continued  from  the  vagina 
throughout  the  entire  organ,  and  thence  into  the  Fallopian  tubes,  along  which 
it  extends  to  their  fimbriated  extremity,  where  it  becomes  continuous  with 
the  peritonaeum  on  each  side,  thus  presenting  a singular  example  of  the  con- 
tinuity of  a mucous  and  serous  membrane  with  each  other,;  the  mucous  mem- 
brane of  the  uterus  is  often  of  a very  dark  color,  and  is  marked  by  several 
lines-  The  cavity  of  the  uterus  is  very  small ; it  is  somewhat  larger  in  the 
superior  fundus  than  elsewhere.  The  Fallopian  tubes  are  from  four  to  five 
inches  in  length;  they  extend  from  the  fundus  uteri  upwards  and  outwards 
at  first,  and  then  a little  downwards  and  backwards;  each  terminates  in  a 
soft  fringed  extremity,  called  Corpus  fimbriulum ; these  canals  arc  narrow 
where  they  join  the  uterus,  but  each  increases  in  size  near  the  corpus  fimbri- 
atum.  The  ovaria  are  two  small,  white,  flattened,  oval  bodies,  one  on  each 
side,  enclosed  in  the  posterior  fold  of  the  broad  ligament,  and  behind  the  Fal- 
lopian tube.  Each  ovary  is  connected  to  the  side  of  the  uterus  by  the  broad 
ligament  of  the  latter,  also  by  a round  fibrous  cord,  the  proper  ligament  of  the 
ovary;  this  is  about  two  inches  long,  and  is  enclosed  between  the  laminae  of 
the  broad  ligament  of  the  uterus.  Each  ovary  is  covered  by  the  peritonaeum, 
which  adheres  very  closely  to  it;  beneath  this  is  a strong  white  fibrous  cap- 
sule, within  which  a number  of  small  vesicles  will  be  found  connected  together 
by  cellular  membrane  and  vessels 


132 


THE  DUBLIN  DISSECTOR, 


CHAPTER  VIII. 

DISSECTION  OF  THE  INFERIOR  EXTREMITIES. 

Each  inferior  extremity  is  connected  to  the  trunk  by  the  strong  ligament? 
of  the  hip  joint,  and  by  several  muscles  which  pass  from  the  pelvis  to  the 
thigh  and  leg.  This  dissection  may  be  performed  while  the  pelvis  remains 
attached  to  the  spine,  or  the  former  may  be  separated  from  the  lumbar  verte- 
brae, and  divided  into  two. 

The  muscles  of  the  lower  extremity  are  classed  into  those  of  the  thigh,  leg, 
and  foot. 


§ 1. — Dissection  of  the  Muscles  of  the  Thigh. 

Place  the  extended  limb  on  the  back  part,  raise  the  integuments  from  the 
anterior  and  lateral  parts  of  the  thigh,  and  from  the  upper  part  of  the  leg ; 
several  cutaneous  nerves,  veins,  and  lymphatic  vessels  are  met  with  in  this 
dissection ; the  nerves  are  branches  of  the  lumbar  plexus,  and  of  the  anterior 
crural  nerve ; they  pierce  the  fascia  lata  near  Poupart’s  ligament,  and  descend 
chiefly  along  the  anterior  and  outer  side  of  the  thigh.  The  cutaneous  veins 
are  branches  of  the  internal  saphena  vein;  this  vessel  will  be  found,  in  dis- 
secting the  leg  and  foot,  to  commence  at  the  inner  side  of  the  latter,  and  to 
ascend  along  the  internal  part  of  the  leg  and  knee  to  the  inner  and  fore-part 
of  the  thigh,  along  which  it  continues  its  course  towards  the  groin  ; and  about 
an  inch  and  a half  below  Poupart’s  ligament  it  pierces  the  fascia  lata,  and 
joins  the  femoral  vein.  In  this  course  the  saphena  vein  receives  several 
cutaneous  branches,  and,  in  general,  just  before  it  ends  in  the  femoral  it  is 
joined  by  one  or  two  large  veins  from  the  outer  and  fore-part  of  the  thigh,  and 
by  some  smaller  branches  from  the  abdominal  parietes ; some  cutaneous 
branches  from  the  anterior  crural,  and  lumbar  nerves  accompany  this  vein  in 
its  course  along  the  thigh.  Beneath  the  integuments  the  thigh  is  invested  by 
the  superficial  fascia,  which  is  prolonged  around  it  from  the  parietes  of  the 
abdomen;  in  the  groin  this  fascia  is  thick  and  laminated,  and  closely  con- 
nected to  the  fascia  lata ; but  inferiorly  and  posteriorly  it  is  thin  and  loose, 
and  differs  but  little  from  the  ordinary  sub-cutaneous  cellular  tissue.  This 
fascia  may  be  easily  detached  from  the  fascia  lata  of  the  thigh,  except  in  the 
groin ; in  attempting  to  raise  it  in  this  region  we  expose  the  superficial  in- 
guinal glands  ; these  are  eight  or  ten  in  number ; five  or  six  of  them  are  placed 
parallel  to  Poupart’s  ligament,  some  above,  others  belowr  it;  two  or  three  are 
situated  lower  down  in  the  groin  than  these,  near  the  termination  of  the  sa- 
phena vein ; these  last  glands  lie  on  the  fascia  lata ; they  are  larger  than  the 
former,  and  are  parallel  to  the  saphena  vein.  Through  these  conglobate  in- 
guinal glands  the  superficial  absorbents  of  the  lower  extremities  pass ; also 
those  from  the  external  parts  of  generation.  Beneath  the  fascia  lata,  and  close 
to  the  femoral  vessels,  are  the  deep-seated  inguinal  glands;  they  are  small, 
and  only  three  or  four  in  number;  the  deep-seated  absorbents  of  the  limb  pass 
through  these.  The  integuments  and  superficial  fascia  having  been  removed, 
the  fascia  lata  may  be  next  examined.  This  aponeurosis  surrounds  the  thigh  ; 


OR  MANUAL  OF  ANATOMY. 


1(T* 

oo 

it  is  very  strong  and  tendinous  externally,  but  so  thin  and  weak  internally, 
that  without  caution  it  is  apt  to  be  removed  along  with  the  integuments;  it  is 
attached  superiorly  and  externally  to  the  crest  of  the  ilium ; posteriorly  to  the 
sacrum  and  coccyx  : on  the  glutaeus  maximus  it  is  very  weak  and  thin,  but  at 
the  anterior  border  of  this  muscle  it  becomes  very  strong,  receiving  an  addi- 
tion of  fibres,  both  from  the  tendon  of  that  muscle,  and  from  the  tensor  vaginae 
femoris;  anteriorly  the  fascia  lata  is  attached  to  Poupart’s  ligament,  and  in- 
ternally to  the  rami  of  the  ischium  and  pubis;  as  this  aponeurosis  extends 
down  the  thigh,  it  confines  the  different  muscles  in  their  situation,  so  as  to 
preserve  the  figure  of  the  limb ; several  processes  also  pass  in  from  its  internal 
surface  to  form  sheaths  for  some  muscles,  and  to  bind  down  others  in  their 
place ; to  many  of  these  processes  the  muscles  adhere,  so  that  when  in  action 
they  serve  to  make  the  fascia  more  tense  and  resisting ; these  processes  also 
serve  to  increase  the  surface  of  origin  or  attachment  of  several  muscles. 
Along  the  posterior  part  of  the  thigh  the  fascia  lata  is  connected  to  the  whole 
length  of  the  linea  aspera,  also  to  the  insertion  of  the  glutaeus  maximus,  and 
to  the  origin  of  the  short  head  of  the  biceps ; inferiorly  it  adheres  to  the  con- 
dyles of  the  femur,  surrounds  the  knee-joint,  and  receives  an  addition  of 
fibres  from  the  different  tendons  in  this  region  ; below  the  knee  it  is  continued 
over  the  heads  of  the  tibia  and  fibula  into  the  fascia  of  the  leg.  Numerous 
foramina  are  observable  in  the  fascia  lata,  particularly  at  the  upper  and  ante- 
rior part  of  the  thigh  ; they  transmit  cutaneous  nerves  and  vessels : the  most 
remarkable  of  these  holes  is  that  for  the  saphena  vein ; it  is  situated  about  an 
inch  and  a half  below  Poupart’s  ligament,  and  may  be  most  distinctly  seen  by 
dividing  the  vein  on  the  fore-part  of  the  thigh,  and  raising  it  towards  the  ab- 
domen ; this  opening  is  semilunar,  the  concavity  directed  upwards  ; from  its 
apparently  sharp  edge  the  fascia  is  reflected  backwards,  and  is  lost  on  the 
sheath  of  the  femoral  vessels.  That  part  of  the  fascia  which  is  internal  to  this 
opening  is  named  the  pubic  portion  of  the  fascia  lata ; it  covers  the  pectinaeus 
muscle,  adheres  to  the  spine  and  linea  innominata  of  the  pubis,  extends  behind 
the  femoral  vessels,  and  is  continuous  with  the  fascia  iliaca;  that  part  of  the 
fascia  lata  external  to  the  saphenic  opening  is  called  the  iliac  portion ; it 
covers  the  sartorius,  tensor  vaginae,  rectus,  and  iliacus  internus  muscles,  and 
is  continued  obliquely  in  front  of  the  femoral  vessels,  in  the  form  of  a crescen- 
tic or  falciform  process,  the  concavity  of  which  is  directed  downwards  and 
inwards;  the  convexity  is  towards  the  ilium,  and  attached  to  Poupart’s  liga- 
ment ; the  lower  cornu  of  this  crescentic  process  is  continuous  with  the  outer 
cornu  of  the  saphenic  opening,  and  the  upper  cornu  extends  in  front  of  the 
femoral  vessels  to  their  inner  side,  and  is  inserted  along  with  the  third 
insertion  of  Poupart’s  ligament  into  the  linea  innominata,  or  the  ilio  pectinaea: 
between  the  margin  of  the  falciform  process  and  the  pubic  part  of  the  fascia 
lata  is  a thin  membrane,  perforated  by  numerous  vessels,  this  is  termed  the 
cribriform  fascia;  it  is  connected  on  either  side  to  the  iliac  and  pubic  portions 
of  the  fascia  lata,  and  extends  from  the  saphena  vein  to  Poupart’s  ligament, 
in  front  of  the  femoral  vessels ; it  adheres  to  the  anterior  part  of  the  sheath  of 
the  latter,  or  to  the  fascia  transversalis ; when  this  cribriform  fascia  is  re- 
moved, the  falciform  process  is  made  more  distinct.  (See  Description  of 
Crural  Hernia,  page  82.)  The  fascia  lata,  in  some  situations,  particularly 
along  the  outer  side  of  the  limb,  is  seen  to  consist  of  two  laminae  of  fibres ; the 


134 


THE  DUBLIN  DISSECTOR. 


external  take  a circular,  the  internal  a longitudinal  direction;  these  two 
laminae  are  very  distinctly  separated  at  the  upper  and  outer  part  of  the  thigh 
by  the  insertion  of  the  tensor  vaginae  femoris;  the  deep  layer,  which  in  this 
situation  is  very  strong,  is  attached  to  the  capsular  ligament  of  the  hip  joint, 
and  to  the  external  head  of  the  rectus  muscle.  Raise  the  fascia  lata  from  the 
anterior  and  lateral  parts  of  the  thigh,  several  muscles  will  come  into  view, 
the  femoral  vessels  also  in  the  groin  will  be  partially  exposed,  thev  are  still 
somewhat  concealed  by  a quantity  of  adipose  substance,  and  by  a few  deep- 
seated  lymphatic  glands;  when  these  are  removed,  we  always  find  the  vein 
internal  to  the  artery,  and  about  an  inch  and  a half  from  the  spine  of  the 
pubis ; immediately  external  to  the  vein  is  the  artery  resting  on  the  psoas,  and 
about  a quarter  of  an  inch  external  to  the  artery  is  the  anterior  crural  nerve, 
imbedded  between  the  psoas  and  iliacus,  and  covered  by  the  fascia  iliaca,  it 
does  not  therefore  lie  in  the  sheath  of  the  vessels.  Clean  the  several  muscles 
which  now  partially  appear  on  the  fore -part  of  the  thigh  : external  to  the  ves- 
sels, the  sartorius  and  tensor  vaginae  are  first  seen  ; internal  to  the  vessels  are 
the  pectinaeus,  gracilis,  and  the  three  adductors,  and  immediatelv  covering 
the  anterior  and  lateral  part  of  the  femur  are  the  rectus,  cruraeus,  vastus 
interims,  and  externus. 

MUSCLES  ON  THE  FORE-PART  AND  SIDES  OF  THE  THIGH. 

Tensor  vaginae  femoris,  at  the  upper  and  outer  part  of  the  thigh,  narrow 
above,  broad  and  thin  below,  arises  tendinous  and  fleshy  from  the  external 
part  of  the  anterior  superior  spinous  process  of  the  ilium;  it  forms  a fleshv 
belly,  which  descends  obliquely  backwards,  and  is  inserted,  broad  and  thin, 
into  a duplicature  of  the  fascia  lata  on  the  outside  of  the  thigh,  about  three 
inches  below  the  great  trochanter;  use,  to  make  tense  the  fascia,  to  rotate  the 
thigh  inwards  ; also,  to  assist  in  flexing  and  abducting  it.  The  origin  of  this 
muscle  is  between  the  sartorius  and  gluteus  inedius;  between  these  muscles 
it  descends,  covered  by  the  fascia  lata ; its  insertion  is  anterior  to  that  of  the 
glutseus  maximus  muscle. 

Sartorius  is  the  longest  muscle  in  the  body,  thin  and  flat  like  a riband, 
broader  in  the  middle  than  at  the  extremities,  situated  obliquely  along  the 
anterior  and  inner  side  of  the  thigh,  arises  by  short  tendinous  fibres  from  the 
anterior  superior  spine  of  the  ilium,  and  from  the  notch  below  that  process,  it 
soon  becomes  broad  and  fleshy,  extends  obliquely  across  the  thigh  to  its  inner 
side,  and  descending  perpendicularly  to  the  knee  passes  behind  the  condyle 
of  the  femur;  it  then  turns  forwards  and  outwards  towards  the  inner  side  of 
the  upper  end  of  the  tibia,  into  which  it  is  inserted  below  the  tubercle,  by  a 
long  flat  tendon,  the  anterior  edge  of  which  is  attached  to  the  fascia  lata  cover- 
ing the  knee  joint,  and  the  posterior  edge  sends  off  an  aponeurosis  to  the  fas- 
cia of  the  leg.  Use,  to  flex  the  leg  upon  the  thigh,  also  the  latter  on  the  pelvis  ; to 
adduct  the  thigh  and  leg  obliquely,  so  as  to  cross  the  lower  extremities ; when 
the  thigh  and  leg  are  extended,  it  assists  in  raising  and  advancing  forwards 
the  whole  limb,  also  in  turning  the  knee  outwards ; when  the  knee  is  bent,  it 
may  turn  the  leg  and  toes  inwards ; in  standing,  it  also  supports  the  pelvis 
and  prevents  it  bending  backwards  on  the  thigh.  This  muscle  through  its 
whole  extent  is  covered  only  by  the  fascia  lata  and  the  integuments,  its 


0U  MANUAL  OF  ANATOMY. 


135 


superior  extremity  lies  between  the  tensor  vaginae  and  the  iliacus  interims  mus- 
cles; its  inferior  extremity  expands  into  a strong  aponeurosis,  which  covers 
and  adheres  to  the  tendons  of  the semi-tendinosus  and  gracilis  muscles;  in  its 
course  along  the  thigh  it  first  passes  over  the  psoas,  iliacus,  and  rectus  mus- 
cles, next  over  the  abductor  muscles  and  the  femoral  vessels,  from  which  it  is 
separated  by  a strong  aponeurosis;  inferiorly  it  passes  over  the  internal  lateral 
ligament  of  the  knee,  between  the  tendons  of  the  abductor  magnus  and  the 
gracilis.  The  superior  third  of  this  muscle  extends  in  an  oblique  direction 
from  the  ilium  downwards  and  inwards,  forms  the  external  boundary  of  the 
inguinal  region,  and  lies  to  the  outer  side  of  the  femoral  vessels ; the  middle 
third  is  more  vertical  in  its  course,  and  is  here  about  two  inches  broad,  and 
completely  covers  the  femoral  vessels,  also  a part  of  the  adductor,  and  vastus 
internus  muscles. 

Rectus  Femoris,  long  and  flat,  rather  round  in  the  centre,  placed  vertically 
on  the  fore-part  of  the  thigh,  arises  by  two  tendons,  one  short,  strong,  anterior 
and  internal,  from  the  anterior  inferior  spinous  process  of  the  ilium,  the  other 
longer,  broader,  and  more  curved  from  the  superior  and  external  border  of 
the  acetabulum,  and  from  the  capsular  ligament;  these  tendons  soon  uniting 
form  a strong  fleshy  belly,  which  descends  almost  vertically,  with  a slight 
inclination  inwards ; this  muscle  has  a peculiar  penniform  appearance,  it  is 
also  tendinous  anteriorly  in  the  upper  half,  so  that  the  sartorius  can  glide  over 
it,  and  tendinous  posteriorly  in  the  lower  half,  whereby  it  can  move  on  the 
surface  of  the  cruraeus.  This  muscle  ends  in  a flat  tendon,  which  is  inserted 
along  with  the  vasti  and  cruraeus  into  the  upper  edge  of  the  patella,  a 
few  fibres  pass  anterior  to  this  bone,  and  are  continued  into  the  ligamentum 
patellae,  which  descends  obliquely  outwards  to  the  tubercle  of  the  tibia.  Use, 
to  extend  the  leg  on  the  thigh,  and  to  flex  the  thigh  on  the  pelvis ; it  also  sup- 
ports and  draws  forwards  the  pelvis  on  the  thigh,  and  strengthens  the  capsular 
Iigament  of  the  hip  joint.  The  anterior  tendinous  origin  of  this  muscle  is 
covered  by  the  sartorius,  tensor  vaginae  and  iliacus  internus  muscles,  the  pos- 
terior by  the  glutaeus  medius  and  minimus  muscles;  the  remainder  of  the 
muscle  is  only  covered  by  the  integuments  and  fascia  ; superiorly  this  muscle 
lies  on  the  capsular  ligament  of  the  hip  joint  and  the  external  circumflex  ves- 
sels ; in  the  rest  of  its  course  on  the  crurceus  and  vasti  muscles,  to  which  it  is 
united  below,  so  that  some  describe  these  four  as  one  muscle,  under  the  name 
of  quadriceps  extensor  cruris.  Beneath  the  rectus  we  find  this  large  mass  of 
muscular  substance,  covering  the  front  and  sides  of  the  femur;  it  may  be 
divided  superiorly  into  three  portions,  but  inferiorly  these  are  inseparably 
united;  the  external  portion  is  named  vastus  externus,  the  internal,  vastus 
internus,  and  the  middle,  crurasus. 

Vastus  Externus,  much  larger  than  the  other  portions,  and  larger  above 
than  below,  arises- from  the  root  and  {interior  part  of  the  great  trochanter, 
anterior  to  the  tendon  of  the  glutaeus  maximus,  from  the  outer  edge  of  the 
linea  aspera,  and  from  the  oblique  ridge  which  leads  to  the  external  condyle, 
anterior  to  the  short  head  of  the  biceps  ; from  all  the  external  surface  of  the 
bone,  and  from  the  fascia  lata,  the  fibres  descend  obliquely  forwards;  the 
superior  are  very  long,  the  inferior  are  shorter  and  more  transverse,  inserted 
into  the  external  surface  of  the  tendon  of  the  rectus,  also  into  the  side  of  the 
patella,  and  by  an  aponeurosis  which  adheres  to  the  synovial  membrane  of  the 


136 


THE  DUBLIN  DISSECTOR, 


knee-joint,  into  the  head  of  the  tibia.  Use,  to  extend  the  knee,  also  to  rotate 
the  leg  outwards;  this  muscle  is  partly  concealed  by  the  rectus  ; its  external 
surface  is  tendinous  above  and  fleshy  below,  its  internal  is  fleshy  above  and 
tendinous  below. 

Vastus  Internus,  smaller  and  shorter  than  the  last,  arises  on  the  anterior 
part  of  the  femur,  from  the  inter-trochanteric  line ; from  the  inner  edge  of 
the  linea  aspera,  its  whole  length,  also  from  the  inner  side  of  the  femur,  the 
fibres  descend  obliquely  forwards,  and  are  inserted  into  the  inner  edge  of  the 
tendon  of  the  rectus,  also  into  the  patella,  and  by  an  aponeurosis,  which  covers 
the  inner  side  of  the  synovial  membrane  of  the  knee,  into  the  head  of  the  tibia. 
Use,  to  extend  the  knee  and  turn  the  leg  a little  inwards.  The  vastus  inter- 
nus is  partly  concealed  by  the  rectus  and  sartorius,  its  origin  lies  anterior  to 
the  insertion  of  the  psoas,  pectinaeus,  and  adductor  muscles,  and  overlaps  the 
cruraeus,  so  as  to  be  in  contact  with  the  vastus  externus ; its  internal  surface 
is  tendinous  above  and  fleshy  below ; an  aponeurosis  from  the  two  vasti  covers 
the  patella  and  its  ligament,  also  the  sides  of  the  joint;  this  aponeurosis  is 
inserted  into  the  head  of  the  tibia,  it  serves  to  support  the  patella  in  its  situa- 
tion, and  to  protect  the  sides  of  the  articulation  like  a capsular  ligament;  a 
small  bursa  is  situated  over  the  patella,  between  this  aponeurosis  and  the  skin  ; 
the  insertion  of  the  vastus  externus  into  the  patella  overlaps  that  of  the  vastus 
internus,  and  both  overlap  the  crurseus,  from  which  the  vastus  externus  can 
be  more  easily  separated  above,  but  the  vastus  internus  below. 

Crur.eus,  shorter  than  either  of  the  vasti,  between  which  it  lies,  larger  and 
more  tendinous  below  than  above,  arises  fleshy  from  the  anterior  and  external 
part  of  the  femur,  commencing  at  the  inter-trochanteric  line,  and  extending 
along  three-fourths  of  the  bone,  as  far  outwards  as  the  linea  aspera  : it  does 
not  adhere  to  the  inner  side  of  the  femur,  there  being  a portion  of  the  latter, 
nearly  an  inch  in  breadth  and  extending  almost  the  whole  length  of  the  bone, 
to  which  no  muscular  fibre  adheres ; the  crurseus  descends  close  to  the  femur 
to  its  inferior  third,  the  fibres  then  incline  forwards,  become  tendinous  poste- 
riorly, and  are  separated  from  the  bone  by  a large  bursa,  and  by  a consider- 
able quantity  of  fat;  inserted  into  the  upper  and  outer  edge  of  the  patella, 
also  into  the  synovial  membrane  of  the  knee  behind  the  vasti,  particularly  die 
external,  to  which  it  is  here  intimately  united.  Use,  to  assist  the  vasti  and 
the  rectus  in  extending  the  leg.  This  muscle  is  covered  bv  the  rectus  and 
the  vasti,  from  the  latter  it  can  only  be  separated  superiorly  by  tearing  a few- 
muscular  fibres,  and  tracing  some  large  nerves  and  vessels  that  pass  between 
them.  The  large  bursa,  which  is  situated  behind  the  lower  part  of  this  mus- 
cle, is  attached  to  and  frequently  communicates  with  the  synovial  membrane 
of  the  joint;  a few  muscular  fibres  are  generally  attached  to  this  membrane, 
and  have  been  described  as  a distinct  muscle,  the  sub-crural  or  capsular, 
this  arises  from  the  anterior  surface  of  the  femur,  about  its  inferior  fourth, 
passes  forwards  and  downwards,  and  is  inserted  into  the  synovial  membrane. 
Use,  to  raise  the  synovial  membrane  in  extension  of  the  leg,  so  as  to  prevent 
its  being  contused  by  the  patella. 

Gracilis,  flat,  long,  and  thin,  broad  and  fleshy  above,  round  and  tendinous 
below,  situated  at  the  inner  side  of  the  thigh,  immediately  beneath  the  integu- 
ments and  fascia;  arises  by  a thin  short  tendon  from  the  lower  half  of  the 
symphysis,  and  from  the  inner  edge  of  the  descending  ramus  of  the  pubis;  it 


011  MANUAL  OF  ANATOMY, 


*37 


soon  becomes  fleshy,  and  descends  vertically,  one  edge  directed  forwards,  the 
other  backwards,  and  its  surfaces  looking  one  inwards,  the  other  outwards; 
about  the  inferior  fifth  of  the  thigh  it  ends  in  a round  tendon  which  passes 
behind  the  inner  condyle,  and  then  turns  forwards  along  with  the  tendon  of. 
the  sartorius,  behind  and  beneath  which  it  lies  ; inserted  into  the  superior  part 
of  the  internal  surface  of  the  tibia,  uniting  with  the  sartorius  and  semi-tendi- 
nosus.  Use,  to  adduct  the  leg  and  thigh,  to  bend  the  knee,  and  turn  the  leg 
and  foot  inwards.  The  origin  of  the  gracilis  is  between  the  triceps  and  the 
crus  penis;  its  whole  course  is  superficial,  except  near  the  knee,  where  it  is 
covered  by  the  sartorius ; its  insertion  is  inferior  to  that  of  the  sartorius,  and 
superior  to  that  of  the  semi-tendinosus ; the  saphena  vein  and  nerve  are 
situated  between  its  tendon  and  that  of  the  sartorius  at  the  inner  side  of  the 
knee,  but  these  are  separated  from  each  other  by  a fascia,  which  attaches  these 
tendons  together,  the  vein  lying  superficial : from  the  tendon  of  the  gracilis  an 
aponeurosis  is  sent  off  to  the  fascia  of  the  leg. 

Pectinjeus,  flat,  triangular,  broad  above,  situated  at  the  superior,  anterior, 
and  internal  part  of  the  thigh ; arises  fleshy  from  the  linea  innominata  on  the 
horizontal  ramus  of  the  pubis,  between  the  spine  of  that' bone  and  the  ilio- 
pectinzeal  eminence;  it  forms  a flat  fleshy  belly,  which  descends  obliquely 
outwards  and  backwards,  and  is  inserted  by  a flat  tendon  into  the  rough  ridge 
which  leads  from  the  lesser  trochanter  to  the  linea  aspera.  Use,  to  adduct 
and  flex  the  thigh,  also,  to 'rotate  it  outwards  ; it  may  also  serve  to  strengthen 
the  capsular  ligament  of  the  hip  joint  internally,  and  in  adduction  of  the 
limb  to  draw  the  capsule  inwards  from  between  the  neck  of  the  femur  and 
the  acetablulum.  The  pectinseus  lies  between  the  psoas  magnus  and  the  ad- 
ductor longus ; the  latter  overlaps  it;  it  is  covered  superiorly  by  the  fascia 
lata,  and  interiorly  by  the  femoral  vessels  ; it  covers  the  obturator  nerve  and 
vessels,  the  external  obturator  muscle,  and  the  adductor  brevis  ; it  also  adheres 
to  the  capsular  ligament  of  the  hip  joint. 

Triceps  Adductor  Femoris,  consists  of  three  portions,  which  pass  in 
distinct  laminae  from  the  pelvis  to  the  thigh. 

Adductor  Longus,  flat  and  triangular,  broad  below,  is  situated  at  the  upper 
and  internal  part  of  the  thigh,  superficial  to  the  other  adductors  and  to  the 
pectinneus ; it  arises  by  a short,  small,  but  strong  tendon  from  the  anterior 
surface  of  the  pubis,  between  its  spine  and  the  symphisis;  this  ends  in  a 
broad  fleshy  belly,  which  descends  obliquely  backwards  and  outwards,  and 
is  inserted  by  a broad  thin  tendon  into  the  middle  third  of  the  linea  aspera, 
between  the  adductor  magnus  and  the  vastus  internus,  to  both  of  which  it  is 
closely  united.  The  origin  of  this  muscle  lies  between  the  pectinmus  and 
the  gracilis,  and  above  the  adductor  brevis;  its  insertion  is  behind  the  vastus 
internus,  and  in  front  of  the  adductor  magnus ; this  adductor  is  covered  by 
the  integuments  and  fascia  superiorly,  and  by  the  sartorius  ami  the  femoral 
vessels  interiorly;  it  lies  anterior  to  the  two  following  muscles. 

Adductor  Brevis,  short,  flat,  and  triangular,  is  situated  posterior  to  the 
adductor  longus  and  pectimsus,  and  internal  to  the  psoas;  arises  flat  and 
tendinous  from  the  anterior  inferior  surface  of  the  pubis,  between  the  sym- 
phisis and  the  thyroid  hole;  it  soon  ends  in  a fleshy  belly,  which  passes  out- 
wards, backwards,  and  a little  downwards,  inserted,  by  tendinous  slips  into 
the  superior  third  of  the  internal  root  of  < he  linea  aspera,  extending  for  about 
IS 


138 


THE  DUBLIN  DISSECTOR, 


three  inches  below  the  lesser  trochanter.  The  origin  of  this  muscle  i3  ex- 
ternal to  the  gracilis,  and  concealed  by  the  adductor  longusand  thepectinseus; 
as  it  descends  it  is  covered  by  these  muscles,  except  a small  portion  near  its 
insertion,  which  appears  between  them  ; this  portion  is  posterior  to  the  femoral 
and  profunda  vessels ; its  insertion  is  anterior  to  that  of  the  adductor  magnus ; 
in  the  tendon  of  this  adductor  one  or  two  large  openings  frequently  exist  for 
the  passage  of  some  of  the  perforating  arteries. 

Adductor  Magnus,  the  longest  and  largest  of  the  adductors,  triangular, 
the  base  attached  to  the  femur,  the  apex  to  the  pelvis;  arises  chiefly  fleshy 
from  the  anterior  surface  of  the  descending  ramus  of  the  pubis,  external  to 
the  gracilis,  also  from  the  ramus  of  the  ischium,  and  tendinous  from  the 
external  border  of  the  tuberosity  of  the  latter;  the  fibres  pass  outwards  with 
different  degrees  of  obliquity;  those  which  arise  from  the  pubis  ascend 
obliquely  outwards,  those  from  the  ramus  of  the  ischium  pass  outwards  and 
downwards,  and  those  from  the  tuber  ischii  more  directly  downwards ; inserted 
fleshy  into  the  rough  ridge  which  leads  from  the  great  trochanter  to  the  linea 
aspera,  tendinous  and  fleshy  into  the  linea  aspera,  and  by  a lone;  round  tendon 
into  the  internal  condyle  of  the  femur.  The  superior  edge  of  this  muscle  has 
a twisted  appearance,  it  is  nearly  parallel  to  the  quadratus  femoris;  several 
branches  of  the  internal  circumflex  vessels  pass  between  these  muscles,  and 
in  rotation  of  the  leg  inwards  the  lesser  trochanter  projects  between  them  ; 
the  middle  portion,  which  is  inserted  into  the  linea  aspera,  is  internal  to  the 
insertion  of  the  glutaeus  maximus,  and  to  the  origin  of  the  short  head  of  the 
biceps.  This  part  of  the  muscle  is  perforated  by  several  branches  of  the  per- 
forating arteries;  at  the  lower  part  of  the  linea  aspera  this  muscle  appears  to 
separate  into  two  portions,  one  of  which  is  inserted  into  the  linea  aspera, 
between  the  vastus  interims  and  the  short  head  of  the  biceps ; the  other  is 
continued  into  the  long  tendon  which  is  inserted  into  the  inner  condyle.  The 
adductor  magnus  is  covered  internally  by  the  gracilis,  and  anteriorly  by  the 
long  and  short  adductors,  the  pectinaeus,  part  of  the  sartorius,  and  the  femoral 
vessels;  posterior  to  it  are  the  sciatic  nerve,  and  the  hamstring  muscles;  the 
tendinous  insertion  of  the  lower  part  of  this  muscle  is  intimately  connected 
to  the  vastus  internus : about  the  inferior  fourth  of  the  thigh  there  is  a large 
oblique  opening  between  these  two  muscles,  through  which  the  femoral  vessels 
pass  into  the  poplitaeal  space.  Use,  the  three  adductors,  in  addition  to  ad- 
ducting the  limb,  can  rotate  it  outwards;  they  also  serve  to  steady  and  support 
the  pelvis  on  the  thigh;  the  long  and  short  adductors  can  also  flex  the  thigh 
on  the  pelvis,  and  the  adductor  magnus  can  extend  it. 

In  dissecting  the  preceding  muscles,  we  observe  the  following  vessels  and 
nerves. 

The  Femoral  Artery  passes  from  under  Poupart’s  ligament  about  midway 
between  the  symphisis  pubis  and  the  spine  of  the  ilium  ; it  thence,  descends 
obliquely  inwards  and  backwards,  and  about  the  lower  part  of  the  middle 
third  of  the  thigh  it  perforates  the  tendon  of  the  adductor  magnus,  enters  the 
poplitaeal  space,  and  then  receives  the  name  of  poplitaeal  artery.  In  the 
upper  third  of  the  thigh,  or  in  the  inguinal  region,  the  artery  is  covered  only 
by  the  skin,  superficial  fascia,  some  lymphatic  glands,  and  the  fascia  lata ; 
in  the  middle  third  of  the  thigh  it  receives  the  additional  covering  of  the  sar- 
torius, and  beneath  this  a very  strong  tendinous  aponeurosis,  which  passes 


OR  MANUAL  OF  ANATOMY. 


t39 


from  the  tendons  of  the  adductor  longus  and  magnus  over  the  artery  and  vein, 
and  joins  the  tendon  of  the  vastus  internus;  in  this  part  of  the  thigh  the 
artery  is  enclosed  in  a perfect  tendinous  sheath,  consisting  anteriorly  of  the 
aponeurosis  just  mentioned,  posteriorly  and  internally  of  the  tendons  of  the 
adductors,  and  externally  of  the  vastus  internus:  at  the  lower  end  of  the 
sheath  the  artery  passes  into  the  ham  through  a large  oval  opening  which  is 
bounded  superiorly  by  the  adductor  longus  and  magnus,  externally  by  the 
vastus  internus,  internally  by  the  adductor  magnus,  and  interiorly  by  the  united 
tendons  of  the  adductor  magnus  and  vastus  internus.  The  femoral  artery  in 
this  course  first  passes  over  a few  fibres  of  the  psoas,  next  over  the  pectinasus 
and  adductor  brevis,  the  adductor  longus,  and  a small  portion  of  the 
magnus. 

The  femoral  artery,  immediately  below  Poupart’s  ligament,  gives  off,  1st, 
some  cutaneous  branches;  2d,  small  arteries  to  the  inguinal  glands;  3d,  about 
two  inches  below  Poupart’s  ligament,  a very  large  branch,  the  profunda;  4th, 
several  muscular  branches  to  the  sartorius  and  vastus  internus;  and 5th,  just 
before  it  enters  the  ham  the  anastomotica  inagna  which  is  distributed  to  the 
muscle  and  integuments  at  the  inner  side  of  the  knee.  The  profunda  is  the 
largest  branch  of  the  femoral;  it  descends  behind  that  vessel  and  to  its  inner 
side,  and  gives  several  branches  to  the  muscles  of  the  thigh,  namely,  the  ex- 
ternal and  internal  circumflex,  and  the  three  or  four  perforating  arteries. 
(See  Anatomy  of  the  Vascular  System.)  The  femoral  vein  takes  the  same 
course  as  the  artery;  in  the  groin  it  always  lies  to  its  internal  or  pubic  side, 
but  as  it  descends  it  becomes  posterior  to  it.  In  dissecting  the  muscles  on  the 
fore-part  of  the  thigh,  numerous  branches  of  the  anterior  crural  nerve  are 
met  with  ; this  nerve  in  the  groin  is  separated  into  several  branches,  many  of 
these  become  cutaneous,  others  pass  to  the  muscles  on  the  fore-part  of  the 
thigh,  and  two  or  three  accompany  the  femoral  artery;  one  of  these,  the 
nerous  saphenus,  enters  its  tendinous  sheath,  and  descending  along  the  fore- 
part of  the  artery,  as  far  as  the  opening  in  the  tendon  of  the  triceps,  then 
leaves  that  vessel,  descends  between  the  tendons  of  the  sartorius  and  gracilis 
muscles  to  the  inner  side  of  the  knee;  it  there  becomes  cutaneous,  and 
attaching  itself  to  the  saphena  vein,  it  accompanies  this  vessel  along  the  inner 
side  of  the  leg  to  the  internal  ankle.  (See  Anatomy  of  the  Nervous 
System.) 


§ 2. — Dissection  of  the  Posterior  Part  of  the  Thigh. 

Place  the  detached  extremity  on  its  fore-part,  with  a block  beneath  the  hip 
joint,  so  as  to  flex  the  latter  slightly,  and  thus  extend  the  muscles  in  this 
region.  Raise  the  integuments  from  the  posterior  surface  of  the  limb,  from 
the  crest  of  the  ilium  to  the  calf  of  the  leg;  the  cutaneous  nerves  which  are 
met  with  in  this  dissection,  are  branches  from  the  lumbar  nerves,  from  the 
sacral  plexus,  and  from  the  sciatic  nerve.  The  cutaneous  veins  pass  in  dif- 
ferent directions,  some  turn  round  the  inner  side  of  the  limb  to  the  saphena 
vein,  others  penetrate  between  the  muscles  and  join  the  deep  veins  which  ac- 
company the  muscular  or  the  perforating  arteries,  and  others  descend  to  the 
popliteal  space,  and  join  the  popliteal  or  the  lesser  saphena  vein.  The  fascia 
lata  over  the  gluteus  maximus  is  weak,  but  anterior  to  that  muscle,  that  is. 


140 


THE  DUBLIN  DISSECTOR, 


covering  the  gluteus  medius,  it  is  very  strong,  and  adheres  to  the  surface  of 
this  muscle,  and  to  the  crest  of  the  ilium  above  it;  on  the  posterior  part  of 
the  thigh,  the  fascia  is  not  so  dense  as  on  the  outer  or  anterior  part ; interiorly, 
over  the  popliteal  region,  or  the  ham,  it  is  much  stronger  than  above;  from 
the  thigh  it  is  continued  over  the  muscles  of  the  leg,  in  which  situation  it  may 
be  examined  afterwards  : the  fascia  and  integuments  being  removed,  the 
muscles  should  be  cleanly  dissected  ; these  may  be  divided  into  the  muscles 
of  the  hip  and  of  the  thigh. 

DISSECTION  OF  THE  MUSCLES  OF  THE  HIP. 

These  are,  the  three  glutsei,  the  pyriformis,  the  gemini,  the  two  obturator, 
and  the  quadratus  femoris. 

Gluteus  Maximus  covers  the  greater  part  of  the  pelvis,  also  the  upper  part 
of  the  thigh;  it  is  somewhat  square,  one  edge  being  attached  to  the  sacrum, 
the  opposite  edge  to  the  femur,  and  to  the  fascia  lata,  the  other  edges  are  di- 
rected one  upwards  and  forwards,  the  other  downwards  and  backwards.  The 
inferior  edge  is  thick  and  round,  and  covered  by  a great  quantity  of  fat;  this 
forms  the  fold  of  the  nates.  It  is  difficult  to  clean  the  surface  of  the  gluteus 
inaximus,  its  fasciculi  are  so  coarse  and  rough,  this  may  be  facilitated  by  dis- 
secting parallel  to  the  fibres,  that  is,  in  a line  drawn  from  the  sacrum  towards 
the  great  trochanter.  This  muscle  arises  by  fleshy  and  short  aponeurotic 
fibres,  from  the  posterior  fifth  of  the  crest  of  the  ilium,  from  the  rough  surface 
between  the  crest  and  the  superior  semicircular  ridge  on  this  bone,  from  the 
posterior  ilio-sacral  ligaments  and  lumbar  fascia,  from  the  tubercles  on  the 
posterior  surface  of  the  sacrum,  the  side  of  the  coccyx,  and  from  the  great 
sciatic  ligament,  which  last  it  covers ; the  fibres  are  collected  into  distinct 
fasciculi,  which  descend  obliquely  outwards  and  forwards,  nearly  parallel  to 
each  other,  converging  a little  towards  the  thigh ; the  lower  fibres  are  the 
longest,  they  all  form  a strong  and  dense  mass,  particularly  below,  and  end  in 
a flat  and  thick  tendon,  whose  external  surface  is  rough  and  coarse,  but  the 
internal  smooth,  and  lined  by  a bursa  which  separates  it  from  and  allows  it  to 
glide  over  the  great  trochanter ; this  tendon  is  inserted  into  a rough  edge  which 
leads  from  the  trochanter  to  the  linea  aspera,  also  into  the  upper  third  of  that 
line,  and  by  a tendinous  expansion  into  the  fascia  lata,  covering  the  vastus 
externus  muscle.  Use,  to  extend  the  thigh,  also  to  abduct  and  rotate  it  out- 
wards, to  support  the  pelvis  and  the  trunk  on  the  lower  extremity,  also  to  make 
tense  the  fascia  lumborum  and  the  fascia  lata.  The  glutseus  maximus  is 
covered  by  the  integuments,  by  a considerable  depth  of  fat,  and  by  a thin 
fascia;  as  the  latter  approaches  the  upper  edge  of  the  muscle,  it  becomes  more 
strong  and  adherent,  and  is  thence  extended  over  the  anterior  part  of  the 
glutseus  medius,  to  which  it  adheres  very  closely,  and  is  then  inserted  into  the 
crest  and  anterior  spine  the  ilium.  The  glutseus  maximus  covers  all  the 
muscles  on  the  posterior  part  of  the  pelvis,  except  the  anterior  portion  of  the 
gluteus  medius,  which  is  covered  by  the  fascia  just  now  mentioned  ; its  in- 
sertion into  the  linea  aspera  is  above  the  short  head  of  the  biceps,  and  between 
the  vastus  externus  and  adductor  magnus ; a very  large  bursa  lines  its  tendon, 
and  is. expanded  over  the  trochanter  and  a portion  of  the  vastus  externus  ; it 
is  very  thin,  it  usually  contains  much  synovial  fluid,  and  it  is  frequently 


OR  MANUAL  OF  ANATOMY. 


141 


intersected  by  tendinous  bands : a smaller  bursa  is  often  situated  below  it, 
between  the  tendons  of  the  gluteus  maximus  and  vastus  externus. 

Divide  this  muscle  by  a perpendicular  incision,  and  separate  the  edges ; 
several  muscles,  vessels,  &c.  may  be  noticed,  having  the  following  relation  to 
each  other:  commencing  above,  we  see  the  gluteus  medius  muscle,  beneath 
this,  the  pyriformis,  and  between  these,  the  glutaeal  vessels  and  the  superior 
glutaeal  nerve ; below  the  pyriform  muscle  we  remark  the  great  sciatic  and  some 
smaller  nerves,  also  the  sciatic  and  pudic  vessels,  all  escaping  from  the  pelvis 
by  the  lower  part  of  the  sciatic  notch  ; next  in  order  are  thegemini  muscles  sur- 
rounding the  tendon  of  the  obturator  internus,  below  these  is  the  quadratus 
femoris,  parallel  to  the  superior  fibres  of  the  adductor  magnus ; the  great  sciatic 
ligament,  the  tuber  ischii,  and  the  superior  attachment  of  the  hamstring  muscles 
are  seen  in  this  dissection,  also  several  small  arteries  and  veins,  and  a consider- 
able quantity  of  loose  watery  cellular  tissue,  which  surrounds  the  sciatic  nerve 
in  its  course  through  the  depression  between  the  trochanter  and  tuber  ischii. 

Gluteus  Medius,  triangular,  flat,  thinner  than  the  last  described  muscle 
is  exposed  by  dividing  the  glutaeus  maximus  and  dissecting  off  the  strong  fascia 
which  extends  from  its  anterior  edge  to  the  crest  of  the  ilium,  arises  by  fleshy 
and  aponeurotic  fibres  from  the  deep  surface  of  this  fascia,  from  the  three  an- 
terior fourths  of  the  crest  of  the  ilium,  from  the  superior  semicircular  line  or 
ridge  which  leads  from  the  anterior  spinous  process  of  the  ilium  to  the  upper 
part  of  the  sciatic  notch,  and  from  the  surface  of  the  ilium,  above  and  below 
that  ridge ; the  fibres  descend  in  different  directions,  the  middle  perpendicu- 
larly, the  anterior,  which  are  very  short,  and  the  posterior,  which  are  long, 
obliquely ; they  all  converge  into  a strong  anti  broad  tendon,  which  is  inserted 
into  the  upper  and  outer  part  of  the  great  trochanter,  and  is  attached  ante- 
riorly to  the  tendon  of  the  glutaeus  minimus.  Use,  to  abduct  the  thigh;  its 
posterior  fibres  can  extend  and  rotate  it  outwards,  its  anterior  fibres  can  flex 
and  rotate  it  inwards ; it  also  serves  to  maintain  the  pelvis  in  equilibrio  on 
the  femur,  as  when  standing  on  one  leg.  This  muscle  is  covered  in  part  by 
the  glutaeus  maximus ; the  anterior  and  larger  portion  is  covered  only  by  the 
integuments  and  fascia  lata;  it  lies  on  the  glutaeus  minimus,  its  posterior  edge 
is  parallel  to  the  pyriform  muscle,  and  separated  from  it  by  the  glutaeal  ves- 
sels and  nerves  ; the  anterior  edge  is  nearly  parallel  to  the  tensor  vaginae 
muscle,  is  united  to  it  above,  but  separated  from  it  below  by  a quantity  of 
fat,  and  by  several  branches  of  the  external  circumflex  vessels  and  nerves. 

Glutaeus  Minimus,  is  exposed  by  detaching  from  its  origin  the  glutaeus 
medius ; small,  semicircular,  more  tendinous  than  the  last,  it  arises  from  the 
inferior  semicircular  ridge  on  the  dorsum  of  the  ilium,  and  from  the  rough 
surface  between  it  and  the  edge  of  the  acetabulum ; the  fibres  converge  as 
they  descend,  and  end  in  a strong  round  twisted  tendon,  which  is  inserted 
into  the  upper  and  anterior  part  of  the  great  trochanter,  first  passing  over  a 
small  bursa.  Use,  similar  to  the  last,  it  also  strengthens  the  ilio-femoral 
articulation,  and  as  it  adheres  to  the  capsular  ligament,  it  can  draw  this  out 
■of  the  joint  in  abduction  of  the  thigh.  This  muscle  is  covered  by  the  gluteus 
medius,  and  a little  overlapped  by  the  tendon  of  the  pyriformis,  it  covers  the 
capsular  ligament  and  the  external  tendon  of  the  rectus. 

Pyriformis,  is  of  a flattened  triangular  form,  the  base  at  the  sacrum  within 
the  pelvis,  the  apex  at  the  trochanter ; situated  partly  within  the  pelvis,  partly 


142 


THE  DUBLIN  DISSECTOR, 


behind  the  hip  joint,  nearly  parallel  to  the  posterior  border  of  the  glutseus 
minimus;  it  arises  by  three  tendinous  and  fleshy  fasciculi,  from  the  anterior 
or  concave  surface  of  the  2d,  Sd,  and  4th  divisions  of  the  sacrum ; it  also 
receives  a few  fibres  from  the  anterior  surface  of  the  great  sciatic  ligament, 
and  from  the  upper  and  back  part  of  the  ilium;  the  fibres  form  a thick  fleshy 
belly,  which  passing  through  the  great  sciatic  notch,  descends  obliquelv  out- 
wards and  a little  forwards,  and  is  inserted  by  a round  tendon  into  the  upper 
part  of  the  digital  fossa,  at  the  root  of  the  great  trochanter  above  the  tendons  • 
of  the  gemini  and  obturator  muscles,  to  which  it  is  connected.  Use,  to  abduct 
the  thigh,  to  extend  and  rotate  it  outwards,  it  can  also  act  on  the  capsular 
ligament  in  the  same  manner  as  the  glutseus  minimus.  Within  the  pelvis  this 
muscle  lies  on  the  sacrum  and  is  covered  by  the  hypogastric  vessels,  the  sci- 
atic plexus  of  nerves,  and  the  rectum ; the  sciatic  nerve  often  perforates  it, 
near  its  lower  margin;  on  the  dorsum  of  the  pelvis  this  muscle  is  covered  bv 
the  glutseus  maximus,  and  is  parallel  to,  but  not  covered  by  the  glutseus  ine- 
dius;  it  adheres  to  the  capsular  ligament,  and  is  superior  to  the  gemini,  from 
which  it  is  separated  by  the  sciatic  nerve  and  vessels  : this  muscle  divides  the 
sciatic  notch  into  two  parts,  through  the  superior  pass  the  glutseal  vessels  and 
nerves,  through  the  inferior  the  sciatic  and  pudic  vessels,  the  sciatic  nerve 
and  several  smaller  branches  of  the  sacral  plexus  of  nerves.  To  expose  the 
following  five  small  rotator  muscles  of  the  hip  joint,  draw  to  either  side  the 
great  sciatic  nerve,  and  remove  the  surrounding  loose  cellular  tissue. 

Gemelli,  two  small  muscles  behind  the  ilio-femoral  articulation  between 
the  ischium  and  the  trochanter,  the  superior  arises  narrow  and  fleshy  from 
the  spine  of  the  ischium;  the  fibres  pass  outwards  above  the  tendon  of  the 
obturator  interims,  and  are  inserted  with  it  into  the  upper  part  of  the  digital 
fossa  of  the  great  trochanter.  Inferior  arises  also  fleshy  from  the  upper  part 
of  the  tuber  ischii,  and  from  the  great  sciatic  ligament,  the  fibres  run  parallel 
to  the  former,  and  are  also  inserted  into  the  digital  fossa.  Use,  to  rotate  the 
thigh  outwards,  also  to  abduct  it,  to  strengthen  the  capsular  ligament  and  to 
confine  the  obturator  tendon  in  its  situation.  These  muscles  are  concealed 
by  the  glutseus  maximus  and  the  sciatic  nerve ; they  are  placed  between  the 
pyriformis  and  the  quadratus  femoris  muscles : they  form  a sort  of  sheath 
around  the  tendon  of  the  obturator  interims,  and  adhere  to  its  edges ; they 
appear  as  portions  of  this  muscle  added  to  it  as  it  escapes  from  the  pelvis  ? the 
inferior  is  the  larger  of  the  two;  the  superior  is  inserted  between  the  pyri- 
formis and  the  obturator  internus,  and  the  inferior  between  the  tendons  of  the 
obturator  internus  and  externus : they  both  adhere  to  the  capsular  ligament. 

Obturator  Internus,  is  situated  partly  within  the  pelvis  and  partly  behind 
the  ilio-femoral  articulation;  somewhat  triangular,  the  base  within  the  pelvis, 
the  apex  at  the  great  trochanter,  arises  by  aponeurotic  and  fleshy  fibres  within 
the  pelvis  from  the  superior  or  pelvic  surface  of  the  obturator  or  thyroid  liga- 
irient,  and  from  all  the  circumference  of  the  foramen  of  that  name,  except  at 
the  upper  part  where  the  obturator  nerve  and  vessels  pass  through  ; beneath 
these  a ligamentous  arch  is  extended,  and  from  this  some  fibres  of  this  muscle 
proceed;  it  also  arises  from  the  pubis  internally,  and  from  the  ischium  inte- 
riorly, and  from  a thin  but  strong  fascia  of  the  same  name,  which  covers  this 
muscle  and  separates  it  from  the  levator  ani  muscle;  the  fibres  descend 
obliquely  outwards  and  backwards,  converging  towards  the  lesser  sciatic 


OR  MANUAL  OF  ANATOMY. 


143 


notch,  which  is  between  the  spine  and  the  tuberosity  of  the  ischium ; the 
fibres  here  end  in  aflat  tendon,  which  turning  outwards,  winds  round  the 
cartilaginous  pulley-like  surface  which  the  ischium  here  presents,  a loose 
bursa,  and  one,  in  general,  containing  a quantity  of  synovia,  is  here  inter- 
posed between  this  tendon  and  the  bone ; the  tendon  now  runs  outwards  on 
the  dorsum  of  the  pelvis,  between  the  gemini  muscles,  and  is  inserted  into 
the  digital  fossa  of  the  great  trochanter.  Use,  to  abduct  and  rotate  the  thigh 
outwards ; it  may  also  act  on  the  capsular  ligament.  This  muscle  within  the 
pelvis  is  covered  by  the  peritonaeum,  the  pelvic  fascia,  levator  ani  muscle, 
and  by  a strong  aponeurosis,  termed  the  obturator  fascia,  which  serves  to  give 
origin  to  some  fibres  both  of  the  obturator  muscle  and  of  the  levator  ani, 
between  which  it  is  interposed ; the  obturator  fascia  is  the  external  layer  of 
the  pelvic  fascia;  it  adheres  superiorly  to  the  ilium  and  pubis,  and  is  inserted 
interiorly  into  the  great  sciatic  ligament,  into  the  tuberosity  and  ramus  of  the 
ischium,  also  into  the  ramus  of  the  pubis,  it  here  becomes  continuous  with  the 
triangular  ligament  of  the  urethra;  this  fascia  is  closely  connected  to  the 
obturator  internus  muscle,  except  inferiorly  where  the  internal  pudic  nerve 
and  vessels  intervene.  As  the  obturator  tendon  is  passing  through  the  sciatic 
notch,  its  deep  surface  is  divided  into  four  or  five  distinct  tendons,  which  are 
lined  by  the  synovial  membrane,  and  connected  to  each  other  like  so  many 
plaits  or  folds;  the  pudic  vessels  lie  external  to  this  tendon  in  this  situation  ; 
the  continuation  of  the  tendon  to  its  insertion  has  the  same  relations  as  the 
gemini  muscles. 

Quadratus  Femoris,  arises  by  fleshy  and  aponeurotic  fibres  from  the  ex- 
ternal surface  of  the  tuber  ischii,  anterior  to  the  tendon  of  the  semi-membra- 
nosus,  the  fibres  pass  transversely  outwards,  and  are  inserted  tendinous  and 
fleshy  into  the  inferior  and  posterior  part  of  the  great  trochanter,  and  into  the 
posterior  inter-trochanteric  line.  Use,  to  adduct  and  rotate  the  thigh  out- 
wards ; this  muscle  is  covered  by  the  glutaeus  maximus  and  sciatic  nerve ; its 
origin  is  also  concealed  by  the  hamstrings ; it  is  parallel  to  and  between  the 
gemini  and  the  adductor  magnus  ; its  lower  border  is  overlapped  by  the  latter ; 
it  covers  the  obturator  externus,  the  lesser  trochanter,  and  the  insertion  of 
the  psoas  and  the  iliacus.  Divide  this  muscle,  and  a little  dissection  will 
expose  the  following,  particularly  if  the  gracilis,  adductor,  and  pectinmus 
muscles  have  been  previously  removed. 

Obturator  Externus,  situated  at  the  superior,  posterior,  and  internal  part 
of  the  thigh,  somewhat  triangular  or  pyramidal,  the  base  towards  the  pubes, 
the  apex  at  the  trochanter,  arises  fleshy  from  the  inferior  surface  of  the  thy- 
roid or  obturator  ligament,  and  from  the  surrounding  surface  of  the  pubis  and 
ischium,  the  fibres  descend  obliquely  outwards  and  backwards  behind  the 
neck  of  the  femur,  in  a sort  of  notch  or  groove  between  the  tuber  ischii  and 
the  edge  of  the  acetabulum;  here  they  end  in  a strong  tendon,  which  ascends 
a little  behind  the  neck  of  the  femur,  then  runs  directly  outwards  along  the 
inferior  gemellus,  and  adhering  to  the  capsular  ligament,  is  inserted  into  the 
lower  part  of  the  digital  fossa.  Use,  to  adduct  the  thigh,  and  to  rotate  it  out- 
wards ; it  also  supports  and  strengthens  the  inferior  and  posterior  part  of  the 
ilio-femoral  articulation,  particularly  in  abduction  of  the  thigh.  This  muscle 
is  placed  in  a very  deep  situation,  being  covered,  anteriorly,  by  the  adductor 
brevis  and  pectinaeus,  also  by  the  obturator  nerve  and  vessels,  internally  by 


144 


THE  DUBLIN  DISSECTOR, 


the  adductor  muscles,  externally  by  the  joint,  and  posteriorly  by  the  quadratus 
femoris  and  glutseus  maximus. 

The  several  small  muscles  just  described,  in  addition  to  their  individual 
actions,  effect  the  common  purpose  of  strengthening  the  ilio-femoral  articu- 
lation ; the  capsular  ligament  of  this  joint  is  covered  anterior^  by  the  rectus, 
psoas,  and  iliacus;  internally  by  the  pectinseus  and  obturator  externus;  ex- 
ternally by  the  tendon  of  the  rectus,  the  glutaeus  minimus  and  medius,  and 
posteriorly  by  the  pyriform,  gemini,  obturator  tendons,  quadratus  femoris, 
and  glutseus  maximus;  many  of  these  muscles,  like  the  small  capsular  mus- 
cles of  the  shoulder  joint,  guard  against  dislocation  in  the  different  motions 
of  the  limb,  and  also  serve  to  protect  the  capsular  ligament  by  drawing  it  out 
of  the  angle  which  is  formed  between  the  acetabulum  and  the  neck  of  the 
femur  in  the  rotatory  motions  of  the  limb. 

In  dissecting  the  foregoing  muscles,  several  vessels  and  nerves  must  have 
been  remarked ; the  former  are  derived  from  the  hypogastric  or  internal  iliac 
vessels;  the  latter  from  the  sacral  plexus  of  nerves  ; the  arteries  are  the  glu- 
tseal, sciatic,  and  pudic.  The  glutseal  artery  escapes  through  the  upper  part 
of  the  sciatic  notch,  above  the  pyriform  muscle,  and  immediately  divides  into 
several  branches;  these  are  distributed  to  the  three  glutsei  muscles.  The 
sciatic  artery  passes  out  of  the  pelvis  through  the  lower  part  of  the  great 
sciatic  notch,  below  the  pyriformis ; its  principal  branches  descend  between 
the  tuber  ischii  and  the  great  tfochanter,  and  are  lost  in  the  surrounding  mus- 
cles. The  pudic  artery  escapes  from  the  pelvis  along  with  the  last  described 
vessel ; it  soon,  however,  re-enters  the  cavity  through  the  lesser  sciatic  notch, 
and  pursues  its  course  forwards  and  inwards  towards  the  perinaeum  and  pubis, 
lying  at  first  on  the  internal  surface  of  the  obturator  internus,  and  afterwards 
on  the  rami  of  the  ischium  and  pubis,  its  branches  are  distributed  to  the  ex- 
ternal organs  of  generation,  and  to  the  muscles  in  the  perinaeum.  (See  Ana- 
tomy of  the  Vascular  System.)  Each  of  these  arteries  have  their  corresponding 
veins,  which  take  a similar  course,  and  terminate  in  the  internal  iliac  vein. 
The  nerves  which  are  found  in  this  situation  are  the  superior  and  inferior  glu- 
taeal,  the  posterior  cutaneous,  the  pudic,  the  great  and  lesser  sciatic;  these 
are  all  branches  of  the  sacral  plexus.  The  superior  glut  seal  nerve  accompa- 
nies the  glutseal  artery,  and  is  distributed  principally  to  the  glutaeus  medius 
and  minimus  muscles.  The  inferior  glutseal  nerve  escapes  below  the  pyri- 
form muscle,  and  is  distributed  principally  to  the  glutaeus  maximus.  The 
inferior  or  lesser  sciatic  nerve  accompanies  the  last  through  the  sciatic  notch, 
descends  obliquely  inwards  round  the  tuber  ischii,  and  is  distributed  to  the 
surrounding  muscles  and  integuments.  The  posterior  cutaneous  nerve  also 
passes  through  the  lower  part  of  the  great  sciatic  notch,  descends  beneath 
the  glutaeus  maximus,  and  then  becoming  cutaneous,  divides  into  several  long 
branches,  which  may  be  traced  along  the  posterior  surface  of  the  thigh,  even 
to  the  leg,  where  in  general  they  will  be  found  to  communicate  with  the  pos- 
terior cutaneous  nerves  of  that  region.  The  pudic  nerves  take  the  same  course 
as  the  pudic  artery,  and  terminate  in  corresponding  branches.  The  great 
sciatic  or  posterior  crural  nerve,  is  the  largest  nerve  in  the  body;  it  passes 
out  of  the  pelvis  below,  but  often  through  the  pyriform  muscle,  descends  be- 
hind the  hip  joint  in  the  fossa  between  the  trochanter  and  tuber  ischii.  covered 
by  the  glutaeus  maximus,  and  passing  over  the  gemini,  obtuiv.  ar,  and 


OR  MANUAL  OF  ANATOMY. 


145 


quadratus  muscles ; its  course  along  the  back  of  the  thigh,  and  its  branches, 
shall  be  considered  after  the  dissection  of  the  following  muscles 

DISSECTION  OF  THE  MUSCLES  ON  THE  BACK  PART  OF  THE  THIGH. 

The  fascia  in  this  situation  has  been  already  noticed  ; the  muscles  are  only 
three  in  number,  and  are  commonly  called  hamstrings ; the  semi-tendinosus 
and  semi-membranosus  form  the  inner,  the  biceps  the  outer  hamstring. 

Biceps  Flexor  Cruris,  consists  of  a long  and  short  head ; the  long  head 
arises  from  the  outer  and  back  part  of  the  tuber  ischii  in  common  with  the 
semi-tendinosus,  this  descends  obliquely  outwards,  and  soon  ends  in  a thick 
fleshy  belly ; about  the  inferior  third  of  the  thigh  it  joins,  at  an  acute  angle, 
the  short  head,  which  arises  fleshy  from  the  linea  aspera,  between  the  vastus 
externus  and  the  adductors,  commencing  below  the  insertion  of  the  glutseus 
maximus,  and  continuing  to  within  two  inches  of  the  external  condyle;  here 
the  muscle  ends  in  a strong  tendon,  which  descends  at  first  behind  the  knee, 
then  turns  forwards  and  outwards  towards  the  head  of  the  fibula,  into  which 
it  is  inserted;  the  tendon  is  here  divided  in  general  by  the  external  lateral 
ligament  into  two  fasciculi,  the  superficial  of  which,  in  addition  to  its  attach- 
ment to  the  head  of  the  fibula,  is  also  inserted  into  the  fascia  of  the  leg ; and 
the  deep  fasciculus  which  is  also  inserted  into  the  fibula,  sends  some  fibres  to 
the  head  of  the  tibia.  Use,  to  flex  the  knee  joint,  also,  by  its  long  head,  to 
extend  the  thigh  and  rotate  the  whole  limb  outwards;  the  long  head, can  also 
fix  the  pelvis,  and  prevent  it  and  the  trunk  from  bending  forwards  on  the  head 
of  the  femur.  The  superior  fifth  of  this  muscle  is  concealed  by  the  glutaeus 
maximus,  the  remainder  is  covered  by  the  integuments  and  fascia  and  de- 
scends between  the  vastus  externus  and  semi-tendinosus,  forming  the  outer 
hamstring ; the  long  head  passes  over  the  semi-membranosus,  the  sciatic  nerve, 
and  the  triceps  muscles ; it  also  conceals  the  short  head ; inferiorly  the  biceps 
pass  over  the  external  articular  vessels  and  the  external  head  of  the  gastroc- 
nemius muscle,  and  forms  the  outer  hamstring. 

Semi-tendinosus,  large,  flat,  and  fleshy  above,  round  and  tendinous  below, 
arises  by  fleshy  fibres  from  the  tuberosity  of  the  ischium  in  common  with  the 
longhead  of  the  biceps,  also  from  the  tendon  of  the  latter  for  about  three  inches ; 
it  descends  obliquely  inwards,  and  about  four  inches  above  the  knee  it  ends  in 
along  round  tendon,  which  passing  behind  the  head  of  the  tibia,  is  then  reflected 
forwards  between  the  tendon  of  the  semi-membranosus  and  the  internal  head 
of  the  gastrocnemius,  and  is  inserted  into  the  anterior  angle  of  the  tibia  below 
its  tubercle,  inferior  and  posterior  to  the  tendons  of  the  gracilis  and  sarto- 
rious,  to  which  it  is  connected ; from  the  convex  edge  of  the  tendon  an  apo- 
neurosis is  given  oft’,  which  joins  the  fascia  of  the  leg.  Use,  to  flex  the  knee 
and  rotate  the  leg  inwards,  to  extend  the  thigh,  to  support  the  pelvis,  and 
prevent  the  trunk  falling  forwards.  This  muscle  is  covered  superiorly  by  the 
glutaeus  maximus;  the  rest  of  its  course  is  superficial,  a traverse  line  usually 
intersects  it  about  its  centre. 

Semi-membranosus,  beneath  the  semi-tendinosus,  flat  and  aponeurotic  su- 
periorly, thick  and  fleshy  in  the  middle,  round  and  tendinous  below  ; arises 
by  a flat  tendon  from  the  upper  and  outer  part  of  the  tuber  ischii ; this  descends 
obliquely  inwards,  and  ends  in  a fleshy  belly,  which  retains  this  muscular 
19 


146 


THE  DUBLIN  DISSECTOR, 


structure  lower  down  than  either  of  the  former  muscles,  a little  above  the  knee 
it  ends  in  a round  tendon,  which  passes  behind  the  internal  condyle,  and  di- 
xddes  into  three  processes,  one  of  which  passes  outwards,  another  downwards, 
and  a third  forwards;  the  firstis  a broad  aponeurosis,  which  ascends  obliquely 
outwards,  beneath  the  heads  of  the  gastrocnemius  muscle  over  the  back  part 
of  the  knee-joint,  and  is  inserted  into  the  external  condyle  of  the  femur;  this 
aponeurosis  has  been  termed  the  posterior  ligament  of  the  knee-joint,  or  the 
ligament  of  Winslow,  the  second  is  a strong  and  broad  fascia,  which  decends 
over  the  popliteus  muscle,  and  is  inserted  into  the  posterior  part  of  the  heads 
of  the  tibia  and  fibula,  and  is  also  continuous  with  the  deep  fascia  of  the  leg; 
the  third  process  appears  the  continuation  of  the  tendon,  it  turns  forwards  be- 
neath the  internal,  lateral  ligament,  round  the  head  of  the  tibia  into  which  it  is 
irtserted.  Use,  to  extend  the  thigh  on  the  pelvis,  and  to  support  the  latter  on 
the  thigh,  to  flex  the  knee  and  rotate  the  leg  inwards ; it  also  strenghtens  the  back 
part  of  the  knee,  and  can  draw  the  synovial  membrane  out  of  the  angle  of  the 
joint.  This  muscle,  at  its  origin,  lies  external  to  the  other  hamstrings ; it  is 
covered  at  first  by  semi-tendinosus,  biceps,  and  gluteus  maximus,  interiorly 
it  is  superficial ; above  it  passes  over  the  quadratus  femoris  and  adductor  magnus 
muscles ; below  it  overlaps  the  popliteal  vessels,  and  the  internal  head  of  the 
gastrocnemius,  from  which  last  it  is  separated  by  a bursa ; the  sciatic  nerve 
is  on  its  outer,  the  gracilis  on  its  inner  side. 

The  arteries  which  are  met  with  in  the  dissection  of  these  muscles  are 
branches  of  the  sciatic,  circumflex,  perforating  and  articular,  the  numerous 
ramifications  of  these  vessels  are  distributed  to  the  hamstring  and  adductor 
muscles,  and  are  accompanied  by  their  corresponding  veins ; the  principal 
nerve  in  this  situation  is  the  great  sciatic;  from  the  back  part  of  the  hip  joint 
this  large  nerve  decends  along  the  back  of  the  thigh  to  the  upper  part  of  the 
popliteal  space,  where  it  divides  into  the  peronaeal  and  posterior  tibial  nerves: 
in  this  course  it  is  covered  at  first  by  the  gluteus  maximus,  afterwards  by  the 
biceps  and  semi-tendinosus,  and  interiorly  by  the  integuments  and  fascia ; hav- 
ing passed  over  the  quadratus  femoris  and  the  other  small  muscles  at  the  back 
of  the  hip  joint,  it  next  lies  on  the  adductor  magnus,  and  interiorly  on  a quan- 
tity of  adipose  substance.  The  sciatic  nerve  gives  off  several  cutaneous  and 
muscular  filaments  in  addition  to  its  two  terminating  branches,  the  peronaeal 
and  the  posterior  tibial ; the  peronaeal  nerve  takes  the  course  of  the  biceps 
tendon  towards  the  head  of  the  fibula,  where  it  divides  into  several  branches 
which  are  distributed  to  the  integuments  and  muscles  on  the  outer  and  fore- 
part of  the  leg,  as  will  be  described  in  the  dissection  of  that  region.  The  pos- 
terior tibial  nerve  accompanies  the  popliteal  vessels  through  the  space  of  that 
name,  which  space  the  student  should  next  examine. 

The  popliteal  space  is  situated  behind  the  knee-joint,  extending  upwards  for 
about  one-fourth  of  the  thigh,  and  downwards  for  about  one-sixth  of  the  leg  ; it 
is  somewhat  oval,  is  bounded  internally  by  the  inner  hamstring,  and  the  internal 
head  of  the  gastrocnemius ; externally  by  the  biceps,  external  head  of  the 
gastrocnemius,  and  the  plantaris ; it  is  covered  by  the  integuments  and  by  a 
strong  fascia,  which,  derived  from  the  fascia  lata,  is  strengthened  by  adhering 
to  the  condyles  of  the  femur,  and  to  the  adjoining  tendons  ; this  fascia  serves  to 
approximate  the  side  of  this  region,  and  thus  to  give  to  it  a considerable 
depth.  The  popliteal  space  is  bounded  before  by  the  flat  surface  of  the  lemur. 


OR  MANUAL  OF  ANATOMY. 


147 


by  the  back  part  of  the  joint  covered  by  the  ligament  of  Winslow,  by  the  head 
of  the  tibia,  and  by  the  poplitaeus  muscle ; in  this  region  are  contained  the 
terminating  branches  of  the  sciatic  nerve,  the  popliteal  artery  and  vein  with 
their  branches ; also  some  lymphatic  glands  and  much  adipose  substance.  The 
nerves  are  superficial  and  external  to  the  vessels,  that  is,  nearer  to  the  biceps; 
the  vessels  are  close  to  the  bone,  and  near  to  the  semi-membranosus  muscle, 
the  vein  being  superficial  and  a little  to  the  outer  side  of  the  artery ; two  or 
three  lymphatic  glands  are  connected  to  the  latter ; and  a quantity  of  fat, 
which  is  of  a peculiar  soft  consistence,  intervenes  between  the  nerve  and 
vessels.  The  course  of  the  peronaeal  nerve  and  vessels.  The  course  of  the 
peronseal  nerve  has  been  already  noticed  ; the  posterior  tibial  nerve  descends 
nearly  vertically  between  the  heads  of  the  gastrocnemius,  runs  beneath  the 
solceus,  and  over  the  poplitaeus,  and  then  accompanies  the  posterior  tibial  ves- 
sels  down  the  leg,  and  along  the  inner  side  of  the  heel  to  the  sole  of  the  foot, 
in  which  course  it  shall  be  examined  afterwards ; in  the  ham  this  nerve  sends 
off  muscular  branches,  also  the  posterior  or  external  saphenus  nerve,  which 
accompanies  the  posterior  saphena  vein  along  the  back  of  the  leg,  towards  the 
outer  ankle,  behind  which  it  passes  to  the  external  and  superior  part  of  the 
foot,  where  it  is  distributed ; this  nerve  is  by  some  called  “ communicans 
tibialis.”  The  popliteal  artery  descends  obliquely  outwards  through  this 
space,  and  at  the  lower  edge  of  the  poplitaeus  muscle  divides  into  the  anterior 
and  posterior  tibial  arteries;  in  this  course  it  sends  off  many  muscular  and 
five  articular  branches,  the  latter  supply  the  ends  of  the  bones,  and  the  syno- 
vial membrane  of  the  knee  joint.  The  popliteal  vein  accompanies  the  artery, 
lying  superficial  and  somewhat  external  to  it;  it  receives  branches  which 
correspond  to  those  of  the  artery ; and  it  is  joined  interiorly  by  the  lesser  or 
posterier  saphena  vein.  Next  proceed  to  the  dissection  of  the  leg. 

§ 3. — Dissection  of  the  Leg. 

Remove  the  integuments  of  the  leg  and  foot;  on  the  plantar  surface  of  the 
latter  they  are  always  remarkably  hard  and  thick,  even  in  the  foetus,  particu- 
larly beneath  the  heel  and  the  first  and  last  joints  of  the  toes;  in  these 
situations  also  the  subcutaneous  fat  has  a peculiar  granulated  structure,  being 
intersected  by  tendinous  bands,  which  pass  from  the  skin  to  the  plantar 
fascia.  Beneath  the  integuments  of  the  leg  we  find  two  cutaneous  veins,  the 
internal  and  external  saphena;  the  internal  saphena  is  large  and  regular,  and 
has  numerous  branches ; it  commences  by  small  veins  from  the  upper  surface 
of  the  toes,  and  from  the  dorsum  of  the  foot;  these  run  towards  the  inner 
malleolus  and  unite  in  one  large  vessel,  which  ascends  along  the  inner  side  of 
the  leg,  receiving  in  its  course  numerous  branches  from  the  integuments^  it 
then  passes  behind  the  inner  condyle  of  the  femur,  and  ascending  along  the 
inner  and  anterior  part  of  the  thigh,  it  terminates  in  the  femoral  vein  about  an 
inch  and  a half  below  Poupart’s  ligament;  on  the  thigh  this  vein  is  accompa- 
nied by  small  nerves,  which  are  derived  from  the  lumbar  plexus  and  from  the 
anterior  crural ; along  the  leg  the  saphenus  nerve,  a branch  of  the  anterior 
crural,  is  attached  to  it,  and  winds  round  it.  The  posterior  or  external 
saphena  vein  commences  behind  the  external  ankle  from  the  junction  of 
several  small  veins  from  the  integuments  of  the  heel  and  sole  of  the  foot;  it 


148 


THE  DUBLIN  DISSECTOR, 


ascends  along  the  surface  of  the  gastrocnemius  muscle,  accompanied  by  the 
communicans  tibialis  nerve ; at  the  ham  this  vein  in  general  joins  the  popliteal 
vein,  but  sometimes  it  here  turns  inwards  and  joins  the  internal  saphena  vein, 
with  which  it  always  communicates  in  its  course  along  the  leg.  Several 
cutaneous  nerves  are  distributed  to  the  leg,  namely,  the  internal  saphenus, 
from  the  posterior  tibial,  and  several  cutaneous  branches  from  the  peronseal 
and  anterior  tibial  nerves  perforate  the  fascia  of  the  leg  on  its  outer  and 
anterior  part,  and  are  distributed  to  the  integuments  of  the  leg  and  foot. 

The  fascia  of  the  leg  is  derived  partly  from  that  of  the  thigh ; it  also 
receives  additional  fibres  from  the  tendons  around  the  knee  joint,  namely,  the 
rectus  and  vasti  anteriorly;  the  vastus  externus  and  biceps  externally;  the 
sartorius,  gracilis,  and  inner  hamstring  internally ; the  fascia  adheres  to  the 
head  of  the  tibia  and  fibula,  to  the  spine  of  the  tibia,  near  its  whole  length,  to 
the  annular  ligaments  of  the  ankle  joint,  and  to  the  malleoli;  it  can  scarcely 
be  said  to  exist  on  the  anterior  surface  of  the  tibia,  which  is  only  covered  by 
the  skin  and  periosteum.  The  fascia  of  the  leg  is  stronger  superiorly  than 
interiorly ; near  the  ankle  it  again  increases  in  strength  from  its  connection  to 
the  malleoli  and  to  the  annular  ligaments;  these  are  two  in  number,  the 
anterior  and  internal.  The  anterior  annular  ligament  is  a little  above  the 
joint;  it  is  somewhat  square,  and  stronger  externally  than  internally ; in  the 
latter  situation  it  is  attached  to  the  malleolar  process  of  the  tibia,  and  to  the 
os  naviculare ; in  the  former  to  the  external  malleolus,  and  to  the  upper  part 
of  the  os  calcis  ; it  consists  of  two  layers,  which,  by  separating  and  re-uniting, 
form  three  rings  or  sheaths  for  the  tibialis  anticus,  and  the  two  extensor  ten- 
dons; the  anterior  tibial  vessels  and  nerves  also  pass  beneath  it.  The 
internal  annular  ligament  is  broader  than  the  anterior;  it  is  attached  to  the 
internal  malleolus,  and  to  the  os  calcis ; it  forms  a sort  of  arch  over  the  groove 
or  canal  in  which  the  three  flexor  tendons,  and  the  plantar  nerves  and  vessels 
run.  The  fascia  of  the  leg  is  thin  posteriorly  : near  the  heel  it  is  indistinct; 
on  either  side  it  is  connected  to  the  sheaths  of  the  tendons  that  pass  round  the 
malleoli;  and  on  each  side  of  the  tendo  Achillis  it  sends  in  a lamina  to  join 
the  fascia  which  covers  the  deep  muscles  of  the  leg.  The  fascia  serves  to  con- 
fine the  muscles  in  their  situation,  and  to  give  origin  to  many  of  their  fibres; 
this  last  effect  is  further  accomplished  by  inter-muscular  bands  or  septa, 
which  pass  in  from  the  fascia,  between  the  extensor  and  peronasi  muscles,  and 
and  are  attached  to  the  tibia  and  fibula  and  inter-osseous  ligament.  From  the 
anterior  annular  ligament,  a thin  fascia  is  extended  over  the  dorsum  of  the 
foot : that  covering  the  sole  of  the  foot,  the  plantar  fascia  is  remarkably 
strong;  it  arises  from  the  extremity  of  the  os  calcis,  narrow  but  thick  and 
strong;  it  passes  forwards,  expands  and  divides  into  three  parts,  which  lie  on 
different  planes,  and  which,  by  sending  in  two  processes,  serve  to  separate 
the  plantar  muscles  into  three  orders,  the  internal,  middle,  and  external ; the 
lateral  portions  of  this  fascia  are  attached  to  the  sides  of  the  tarsus  and  meta- 
tarsus; the  internal  portion  is  the  weakest;  the  middle  division  is  the 
strongest,  and  on  a plane  inferior  to  the  internal ; as  this  middle  portion 
expands  beneath  the  plantar  muscles,  it  is  strengthened  by  transverse  fibres, 
and  near  the  base  of  the  toes  it  divides  into  five  fasciculi,  these  diverge,  and 
opposite  the  head  of  each  metatarsal  bone,  they  each  sub-divide  into  two  fas- 
ciculi ; these  pass  along  the  sides  of  the  metatarso-phalangal  articulations. 


OR  MANUAL  OF  ANATOMY. 


149 


and  are  inserted  into  the  lateral  ligaments  of  these  joints,  and  into  the  sheaths 
of  the  flexor  tendons;  between  these  fasciculi  the  tendons  pass,  also  the 
digital  vessels  and  nerves  of  each  toe  ; the  plantar  fascia  possesses  the  same 
strength  as  ligamentous  structure ; use,  it  serves  to  retain  the  arched  form  of 
the  foot,  and  to  protect  the  plantar  muscles,  vessels,  and  nerves,  from  pres- 
sure; it  also  gives  attachment  to  several  muscular  fibres.  The  muscles  of  the 
leg  may  be  divided  into  those  on  the  anterior,  external,  and  posterior  part. 

DISSECTION  OF  THE  MUSCLES  ON  THE  ANTERIOR  AND  EXTERNAL  PART  OF 

THE  LEG. 

The  muscles  on  the  fore-part  of  the  leg  are  the  tibialis  anticus,  extensor 
pollicis,  extensor  communis,  and  peronaeus  tertius ; the  muscles  on  the  outer 
side  of  the  leg  are  the  peronseus  longus  and  brevis : almost  all  these  muscles 
are  connected  to  each  other  superiorly,  so  that  they  cannot  be  perfectly  sepa- 
rated from  each  other;  they  all  adhere  to  and  partly  arise  from  the  fascia  of 
the  leg,  therefore,  when  exposed,  they  present  a rough  surface  superiorly. 

Tibialis  Anticus,  is  next  the  tibia,  somewhat  triangular,  large  and  fleshy 
above,  tendinous  below,  arises  tendinous  and  fleshy  from  the  outer  part  of  the 
two  superior  thirds  of  the  tibia,  from  the  head  of  the  fibula,  from  the  inner  half 
of  the  inter-osseous  ligament,  from  the  fascia  of  the  leg,  and  from  the  inter- 
muscular septa;  the  fibres  descend  obliquely  inwards,  end  in  a strong  and 
flat  tendon  which  crosses  from  the  outer  to  the  fore-part  of  the  tibia,  runs 
through  a distinct  ring  in  the  annular  ligament,  near  the  internal  malleolus, 
passes  forwards  and  inwards  above  the  astragalus  and  naviculare,  increases 
in  breadth,  and  is  inserted  into  the  inner  side  of  the  great  cuneiform  bone, 
also,  by  a tendinous  slip  into  the  base  of  the  first  metatarsal  bone.  Use,  to 
flex  the  ankle,  to  adduct  the  foot,  and  to  raise  its  inner  edge  from  the  ground; 
to  turn  the  toes  inwards,  also  to  support  the  leg  when  standing,  and  prevent 
it  bending  backwards.  This  muscle  is  superficial  through  its  whole  length  ; 
the  tendon,  at  its  insertion,  is  partly  concealed  by  the  abductor  and  flexor 
pollicis  brevis:  superiorly  this  muscle  is  external  to  the  tibia;  interiorly  it  is 
anterior  to  it : the  extensor  communis, and  extensor  pollicis,  the  anterior  tibial 
vessels  and  nerve  are  to  its  outer  or  fibular  side,  a small  bursa  separates  its 
tendon  from  the  upper  part  of  the  internal  cuneiform  bone;  another  bursa  in 
general  surrounds  it,  as  it  is  passing  over  the  synovial  membrane  of  the  ankle 
joint. 

Extensor  Digitorum  Longus,  arises  tendinous  and  fleshy  from  the  external 
part  of  the  head  of  the  tibia,  from  the  head  of  the  fibula,  and  from  about  three- 
fourths  of  this  bone,  from  part  of  the  inter-osseous  ligament,  from  the  fascia 
of  the  leg,  and  its  inter-muscular  septa ; the  fibres  descend  obliquely  inwards ; 
a little  below  the  middle  of  the  leg  they  end  in  three  fiat  tendons,  which  pass 
under  the  annular  ligament  through  a ring  common  to  these  and  to  the  pero- 
naeus tertius,  and  extend  forwards  over  the  dorsum  of  the  foot,  the  internal  of 
the  three  tendons  here  divides  into  two;  the  four  tendons  now  extend  along 
the  dorsum  of  each  of  the  four  external  toes;  the  great  toe  does  not  receive 
any,  and  are  inserted  into  the  last  phalanx  of  each.  Use,  to  extend  the  toes 
and  flex  the  ankle.  This  muscle  is  superficial ; superiorly,  it  lies  between  the 
tibialis  anticus  and  peronaeus  longus,  and  is  connected  to  both;  in  the  middle 


150 


THE  DUBLIN  DISSECTOR, 


of  the  leg  it  is  between  the  extensor  pollicis  and  peronseus  brevis : along  each 
of  the  toes  these  tendons  sub-divide  at  the  joints  between  the  first  and  second 
phalanges,  into  fasciculi,  which  pass  over  the  sides  of  these  articulations  as 
the  extensor  tendons  do  on  the  fingers ; on  the  dorsum  of  the  toes  also  they 
form  a sort  of  aponeurosis  as  on  the  fingers,  the  tendons  of  the  lumbricales 
and  inter-ossei  as  also  the  tendons  of  the  extensor  brevis  assisting  in  its 
formation. 

Extensor  Pollicis  Proprius,  arises  tendinous  and  fleshy  from  the  inner 
edge  of  the  middle  third  of  the  fibula,4and  from  the  inter-osseous  ligament 
nearly  as  low  down  as  the  ankle : a few  fibres  also  proceed  from  the  lower 
part  of  the  tibia;  the  fibres  descend  obliquely  forwards  to  a tendon,  which 
passes  beneath  the  annular  ligament,  then  runs  forwards  over  the  astragalus, 
naviculare,  and  cuneiforme  internum;  the  tendon  next  passes  over  the  first 
metatarsal  bone,  and  is  inserted  by  two  tendinous  fasciculi,  one  into  the  base 
of  the  first  phalanx,  and  the  other  into  the  base  of  the  second  or  last  phalanx 
of  the  great  toe.  Use,  to  extend  the  great  toe  and  flex  the  ankle ; it  may  also 
adduct  the  foot,  and  rotate  it  inwards.  The  upper  and  middle  portions  of 
this  muscle  are  overlapped  and  concealed  by  the  tibialis  anticus  and  extensor 
communis,  between  which  muscles  it  is  situated  ; its  tendon  is  superficial ; the 
anterior  tibial  nerve  and  vessels  separate  it  from  the  tibialis  anticus  aboVe, 
and  from  the  extensor  communis  below ; it  lies  on  the  fibula  and  inter-osseous 
ligament  above ; interiorly  it  crosses  over  the  tibial  vessels,  the  synovial 
membrane  of  the  ankle  joint,  and  the  bones  of  the  tarsus. 

PeronjEus  Tertius,  or  anticus,  appears  to  be  a portion  of  the  extensor  com- 
munis, and  in  some  cases  cannot  be  separated  from  it;  it  arises  from  the 
anterior  surface  of  the  lower  half  of  the  fibula;  the  fibres  pass  forwards  to  a 
tendon  which  descends  along  with  that  of  the  extensor  communis  beneath  the 
annular  ligament;  it  then  passes  forwards  and  outwards,  and  is  inserted 
broad  and  thin  into  the  base  of  the  fifth  metatarsal  bone,  and  it  frequently 
sends  a band  of  fibres  to  join  the  fourth  tendon  of  the  extensor  communis. 
Use,  to  extend  the  little  toe,  to  flex  the  ankle,  to  abduct  the  foot,  and  raise  its 
outer  edge.  This  muscle  is  sometimes  wanting,  an  additional  tendon  from  the 
extensor  communis  will  then  supply  its  place  ; it  is  superficial ; on  the  foot  it 
conceals  the  extensor  brevis,  which  may  be  next  examined. 

Extensor  Digitorum  Brevis,  situated  on  the  upper  surface  of  the  foot, 
arises  tendinous  and  fleshy  from  the  upper  and  anterior  part  of  the  os  calcis. 
anterior  to  the  groove  for  the  peronasus  longus,  also  from  the  cuboid  bone,  the 
astragalus,  and  the  annular  ligament;  it  forms  a flat  fleshy  belly,  which  passes 
fonvards  and  inwards,  ends  in  four  flat  tendons,  of  which  the  two  internal  are 
the  strongest;  the  little  toe  does  not  receive  any;  these  tendons  are  inserted 
thus : the  first  or  most  internal,  into  the  base  of  the  first  phalanx  of  the  great 
toe  ; the  three  other  tendons  join  the  outer  edge  of  the  corresponding  tendons 
of  the  extensor  digitorum  longus,  and  assist  in  forming  the  aponeurosis  which 
covers  the  dorsum  of  each  toe.  Use,  to  extend  the  toes  and  rotate  the  anterior 
part  of  the  foot  outwards.  This  muscle  is  partly  concealed  by  the  tendons  of 
the  long  extensor  and  peronasus  tertius ; it  projects,  however,  behind  and 
between  them ; the  tendons  cross  the  metatarsal  bones  and  the  inter-ossei 
muscles,  beneath  and  in  a contrary  direction  to  the  long  extensor  tendons. 

The  muscles  on  the  outer  part  of  the  leg  are  the  two  peronsei. 


OR  MANUAL  OF  ANATOMY. 


151 


Peron^us  Longus,  arises  tendinous  and  fleshy  around  the  head  of  the 
fibula,  and  from  the  adjacent  surface  of  the  tibia,  from  the  upper  half  of  the 
external  angle  of  the  fibula,  from  the  fascia  and  inter-muscular  septa,  the 
fibres  descend  obliquely  backwards  and  outwards,  end  in  a strong,  flat  tendon , 
which  passes  behind  the  external  malleolus,  through  a groove  in  the  lower  end 
of  the  fibula,  in  which  it  is  bound  down  by  a strong  aponeurosis,  lined  by  a 
synovial  membrane;  it  then  passes  forwards,  downwards,  and  inwards, 
» through  a similar  groove  in  the  os  calcis  and  cuboid ; it  next  passes  across  the 
sole  of  the  foot,  obliquely  inwards  and  forwards  towards  the  metatarsal  bone 
of  the  great  toe,  into  the  outer  side  of  which,  and  of  the  adjacent  sesamoid 
bone,  it  is  inserted  ; also,  into  the  internal  cuneiform,  and  into  the  base  of  the 
second  metatarsal  bone.  Use,  to  extend  the  ankle  joint,  turn  the  foot  out- 
wards, and  raise  its  outer  edge  from  the  ground ; in  the  leg  this  muscle  is 
superficial,  and  is  situated  between  the  extensor  communis  anteriorly  and  the 
solseus  and  flexor  pollicis  posteriorly ; in  the  sole  of  the  foot  it  is  above  all  the 
muscles  there,  and  cannot  be  seen  until  these  are  removed. 

Peronaeus  Brevis  arises  fleshy  from  the  outer  and  back  part  of  the  lower 
half  of  the  fibula,  and  from  the  inter-muscular  septa ; the  fibres  descend  ob- 
liquely, end  in  a tendon  which  passes  behind  the  external  malleolus  in  the 
same  groove  as  the  peronseus  longus  ; it  then  passes  forwards  through  a dis- 
tinct groove  in  the  os  calcis  above  the  peronseus  longus,  and  is  inserted  into 
the  base  of  the  metatarsal  bone  of  the  little  toe,  and  into  the  os  cuboides.  Use, 
similar  to  the  last.  This  muscle  arises  between  the  extensor  longus  and  pero- 
naeus longus,  and  descends  between  the  peronseus  tertius  and  the  flexor  pol- 
licis longus,  and  partly  concealed  by  the  peronaeus  longus;  it  continues  fleshy 
lower  down  than  it,  and  projects  on  either  side  of  its  tendon  ; it  is  separated 
from  the  peronaeus  tertius  by  the  external  malleolus;  in  the  groove  in  the 
latter  it  is  beneath  the  long  peronseal  tendon,  that  is  nearer  to  the  bone,  but 
on  the  os  calcis  it  is  superior  to  it;  an  aponeurosis  sometimes  unites  its  inser- 
tion to  that  of  the  extensor  tendon  of  the  little  toe. 

In  the  dissection  of  the  foregoing  muscles  we  meet  with  the  anterior  tibia! 
vessels  and  their  branches ; also  the  peronseal  nerve  and  its  divisions.  The 
anterior  tibial  artery  is  a branch  of  the  popliteal ; it  passes  forwards  between 
the  solseus  and  poplitaeus,  perforates  the  inter-osseous  space,  surrounded  by 
some  fibres  of  the  tibialis  posticus  ; it  then  descends  obliquely  inwards  and 
forwards  as  far  as  the  cleft  between  the  first  and  second  metatarsal  bones ; in 
its  course  down  the  leg  it  is  placed  at  first  between  the  tibialis  anticus  and 
extensor  communis,  in  the  middle  of  the  leg,  between  the  former  and  the 
extensor  pollicis,  and  inferiorly  between  the  tendon  of  the  latter  and  that  of 
the  extensor  communis  ; above  it  lies  on  the  inter-osseous  membrane,  below  it 
passes  over  the  tibia,  the  synovial  membrane  of  the  ankle  joint,  the  astragalus, 
navicular  and  cuneiform  bones  and  beneath  the  annular  ligament  and  the 
internal  tendon  of  the  extensor  digitorum  brevis ; in  the  leg  the  anterior  tibial 
artery  sends  off,  first,  the  recurrent  branch,  which  ascends  on  the  outer  and 
fore-part  of  the  head  of  the  tibia,  and  meets  the  external  articular  arteries  3 
second,  in  its  course  along  the  leg,  several  muscular  branches ; third,  near 
the  ankle,  the  two  malleolar  branches,  of  these,  the  external  is  the  larger  and 
inosculates  with  a small  artery  (the  anterior  peronseal)  which  perforates  the 
inter-osseous  ligament  about  two  inches  above  the  ankle  joint;  on  the  tarsus. 


152 


THE  DUBLIN  DISSECTOR, 


the  anterior  tibial  artery  sends  off  the  tarsal  and  metatarsal  branches,  which 
pass  obliquely  outwards,  and  supply  the  inter-ossei  muscles,  the  bones  and 
joints  of  the  tarsus  and  metatarsus ; between  the  two  first  metatarsal  bones  the 
anterior  tibial  divides  into  the  superior  and  inferior  branch  ; the  former  sup- 
plies the  integuments  of  the  great  toe;  the  latter  passes  deep  towards  the  sole 
of  the  foot,  and  joins  the  external  plantar  artery  ; the  anterior  tibial  artery  is 
accompanied  by  two  veins,  which  end  in  the  popliteal  vein.  The  peronaeal 
nerve  winds  around  the  head  of  the  fibula,  perforates  the  peronaeus  longus, 
and  divides  into  several  branches  ; some  of  these  supply  the  peronaeal  muscles, 
others  the  integuments  on  the  outer  and  fore-part  of  the  leg  and  foot ; and  the 
continuation  of  the  peronaeal  nerve  passes  obliquely  forwards  and  downwards, 
and  accompanies  the  anterior  tibial  artery,  lying  in  general  superficial,  and 
to  its  fibular  side. 

DISSECTION  OF  THE  MUSCLES  ON  THE  BACK  OF  THE  LEG. 

These  muscles  may  be  divided  into  a superficial  and  a deep  layer;  the 
former  consists  of  the  gastrocnemius,  solaeus,  and  plantaris;  the  latter  of  the 
tibialis,  posticus,  flexor  pollicis  longus,  flexor  digitorum  communis  and  popli- 
taeus.  The  cutaneous  nerves  and  veins,  and  the  fascia,  have  been  already 
noticed. 

Gastrocnemius,  large  and  thick,  tendinous  below,  fleshy  and  aponeurotic 
above,  and  divided  into  two  heads,  both  of  which  are  somewhat  oval,  convex 
behind,  flat  before;  the  internal,  longer  and  larger  than  the  external ; arises 
from  the  upper  and  back  part  of  the  internal  condyle  of  the  femur,  and  fleshy 
from  the  oblique  ridge  above  it ; the  external  head  arises  in  the  same  manner, 
from  above  the  external  condyle,  but  is  not  so  long  or  large ; the  fibres  of 
each  descend  converging,  and  form  two  fleshy  bellies,  which  unite  a little  below 
the  knee  in  a middle  tendinous  line  ; about  the  middle  of  the  leg  the  muscle 
ends  in  a broad  and  flat  tendon,  which  gradually  unites  with  that  of  the 
solasus,  and  both  form  that  strong  tendon  which  is  commonly  called  the  fen  do 
Achillis , and  which  is  inserted  into  the  lower  and  back  part  of  the  os  calcis. 
Use,  to  extend  the  ankle  joint,  and  thus,  by  raising  the  heel  from  the  ground, 
to  throw  the  weight  of  the  whole  body  forwards  on  the  toes  as  in  progression  ; 
to  flex  the  knee  joint,  also  to  secure  the  articulation  against  displacement,  by- 
preventing  the  condyles  of  the  femur  slipping  backwards  oft'  those  of  the  tibia. 
This  large  muscle  is  superficial,  a small  portion  of  its  internal  head  is  over- 
lapped by  the  semi-membranosus ; its  deep  surface  is  more  aponeurotic  than 
its  superficial ; the  lower  angle  of  the  popliteal  space  separates  its  two  heads  ; 
in  this  angle  the  popliteal  vessels,  the  posterior  tibial  nerve,  and  the  plantaris 
muscle  are  contained ; a bursa  is  placed  between  each  head  of  this  muscle 
and  the  condyle  of  the  femur,  which  it  covers ; the  external  head  conceals  the 
tendon  of  the  poplitaeus;  the  internal  covers  the  deep  processes  of  the  semi- 
membranosus tendon  and  an  intervening  bursa,  also  the  insertion  of  the  popli- 
tmus;  the  gastrocnemius  covers  the  greater  part  of  the  solaeus,  therefore,  to 
examine  the  latter,  detach  the  heads  of  the  gastrocnemius  from  the  condyles, 
and  separate  this  muscle  from  the  solaeus  to  within  two  or  three  inches  of  the 
heel ; the  plantaris  muscle  is  now  also  exposed. 

Plantaris  arises  fleshy  from  the  back  part  of  the  femur  above  the  external 


OR  MANUAL  OF  ANATOMY. 


15S 


condyle,  and  from  the  posterior  ligament  of  the  knee ; it  is  connected  to  the 
external  head  of  the  gastrocnemius,  and  forms  a small  pyramidal  fleshy  belly, 
which  descends  obliquely  inwards,  crosses  the  popliteal  vessels,  and  ends  in 
a flat  tendon  (the  longest  in  the  body)  which  descends  between  the  gastroc- 
nemius and  solaeus ; and  when  the  tendons  of  these  muscles  are  about  to  unite, 
that  of  the  plantaris  becomes  superficial,  it  then  descends  along  the  inner  side 
of  the  tendo  Achillis  to  the  heel,  and  is  inserted  into  the  posterior  part  of  the 
os  calcis,  a little  anterior  to  the  tendo  Achillis;  it  has  also  some  connection 
to  the  plantar  fascia.  Use,,  to  extend  the  foot,  and  turn  it  inwards,  also  to 
make  tense  the  fascia,  and  to  flex  the  knee ; its  origin  is  partly  concealed  by 
the  external  head  of  the  gastrocnemius ; its  tendon  also  is  at  first  covered  by 
this  muscle,  but  interiorly  it  is  superficiaf.  This  muscle  is  sometimes 
wanting. 

SoLiEus,  of  an  oval  flattened  figure,  consists  superiorly  of  two  heads, 
which  are  not  so  distinct  from  each  other  as  those  of  the  gastrocnemius;  the 
external  is  longer  and  larger  than  the  internal,  and  arises  from  the  back  part 
of  the  head  and  from  the  superior  third  of  the  fibula,  behind  the  peronaeus 
longus;  the  internal  head  arises  from  the  middle  third  of  the  tibia  commenc- 
ing below  the  oblique  insertion  of  the  poplitseus;  the  two  heads  are  connected 
by  a strong  tendinous  arch,  beneath  which  pass  the  posterior  tibial  nerve  and 
vessels ; all  the  fibres  descend  and  form  a large  oval  belly,  which  continues 
fleshy  lower  than  the  gastrocnemius ; a tendon  is  formed  first  on  its  super- 
ficial surface,  which  is  gradually  united  to  that  of  the  gastrocnemius  to  form 
the  tendo  Achillis ; this  strong  tendon  is  broad  and  thin  above,  narrow  in  the 
middle,  and  round  and  thick  below,  it  is  composed  of  strong  vertical  fibres 
which  descend  behind  the  os  calcis,  over  a bursa  covering  a cartilaginous  im- 
pression on  that  bone,  and  it  is  inserted  into  a rough  surface  below  that.  Use, 
to  assist  the  gastrocnemius  in  extending  the  ankle;  this  muscle  is  almost 
entirely  concealed  by  the  gastrocnemius ; a little  below  the  middle  of  the  leg, 
however,  it  projects  on  each  side  of  the  tendon  of  the  latter,  and  forms  the 
lower  calf  of  the  leg ; it  covers  the  deep  seated  muscles,  vessels,  and  nerves. 

Detach  the  solaeus  from  its  origin,  and  the  strong  deep  fascia  of  the  leg  is 
exposed ; this  fascia  is  partly  derived  from  the  semi-membranosus  and  popli- 
teeus,  and  partly  from  the  more  superficial  fascia  of  the  leg ; it  adheres  to  the 
tibia  and  fibula,  to  the  solaeus  and  to  the  deep  muscles ; interiorly  this  fascia 
is  strong,  and  is  connected  to  the  sheaths  of  the  tendons  that  pass  behind  the 
melleoli,  and  to  the  internal  annular  ligament  of  the  ankle ; dissect  off  this 
fascia  and  clean  the  four  following  muscles. 

Poplitjeus,  situated  obliquely  at  the  upper  and  back  part  of  the  leg,  behind 
the  knee,  and  above  the  other  muscles  in  this  region,  flat  and  triangular,  arises 
by  a round  tendon  from  a depression  on  the  outer  condyle,  descends  obliquely 
inwards  and  backwards,  above  the  head  of  the  fibula,  and  along  the  external 
semi-lunar  cartilage,  to  which  it  is  connected  by  the  synovial  membrane  of 
the  knee,  and  by  a few  tendinous  fibres ; becomes  broad  and  fleshy,  and  is 
inserted  into  a flat  triangular  surface,  which  occupies  the  superior  fifth  of  the 
posterior  surface  of  the  tibia.  Use,  to  bend  the  knee,  and  when  bent,  to  twist 
the  foot  and  toes  inwards ; it  may  also  assist  when  the  limb  is  extended  in 
rotating  the  knee  outwards ; it  supports  the  external  semi-lunar  cartilage,  and 
moves  it  slightly,  so  as  to  adapt  its  situation  to  the  external  condyle  of  the 
20 


154 


THE  DUBLIN  DISSECTOR, 


femur,  in  the  rotatory  motions  of  the  joint ; the  poplitseus  is  covered  by  the 
gast  rocnemius  and  plantaris,  also  by  the  external  lateral  ligament,  the  popli- 
teal nerve  and  vessels ; it  is  superior  to  the  solseus,  and  passes  over  the  tibio- 
fibular articulation  and  the  back  part  of  the  tibia ; it  is  nearly  parallel  to  the 
upper  part  of  the  plantaris ; the  tendon  is  nearly  surrounded  by  the  synovial 
membrane  of  the  knee,  it  lies  however  external  to  the  cavity  of  the  joint. 

Flexor  Digitorum  Perforans,  broader  in  the  centre  than  at  either  end, 
arises  fleshy  from  the  posterior  flat  surface  of  the  tibia,  commencing  below  the 
poplitpeus,  and  extending  to  within  two  or  three  inches  of  the  ankle,  also  from 
the  fascia  and  inter-muscular  septa;  the  fibres  descend  obliquely  inwards  to 
a tendon  which  passes  behind  the  internal  malleolus,  in  a groove  in  the  tibia 
which  is  lubricated  by  a bursa,  a'Vid  in  which  it  is  confined  along  with  the  ten- 
don of  the  tibialis  posticus  by  the  internal  annular  ligament,  separated,  how- 
ever, from  that  tendon  by  a ligamentous  septum,  each  tendon  also  has  a 
distinct  synovial  sac  : this  tendon  then  turns  forwards  and  a little  outwards 
into  the  sole  of  the  foot,  still  confined  in  a bony  groove,  first  in  the  astragalus, 
and  then  in  the  os  calcis ; in  the  sole  of  the  foot  it  lies  beneath  the  tendon  of 
the  flexor  pollicis,  and  is  connected  to  it  by  a tendinous  slip;  about  the  centre 
of  this  region  it  expands  and  receives  the  insertion  of  the  accessory  muscle,  it 
then  divides  into  four  tendons,  which  pass  to  the  four  outer  toes,  and  opposite 
the  first  phalanx,  each  tendon  enters  a strong  fibrous  sheath  which  is  lined  by 
synovial  membrane ; this  sheath  continues  as  lar  as  the  extremity  of  the 
second  phalanx,  and  contains  also  the  corresponding  tendon  of  the  flexor  digi- 
torum  brevis  ; opposite  the  base  of  the  second  phalanx;  each  of  the  last  named 
tendons  is  slit  for  the  transmission  of  the  long  flexor  tendon,  which  continues 
to  run  forwards  to  be  inserted  into  the  last  phalanx  of  each  of  the  four  lesser 
toes.  Use , to  flex  the  toes  and  the  metatarsus,  to  extend  the  ankle,  and  to 

steady  the  leg  on  the  foot  as  when  standing.  This  muscle  in  the  leg  is  covered 
by  the  superficial  muscles,  the  deep  fascia,  and  the  tibial  vessels ; it  overlaps 
the  tibialis  posticus,  and  is  on  the  inner  or  tibial  side  of  the  flexor  pollicis ; a 
little  above  the  inner  ankle,  the  tendon  of  the  tibialis  posticus  crosses  above 
that  of  the  flexor  communis,  that  is,  becomes  nearer  to  the  tibia ; in  the  sole 
of  the  foot  its  direction  is  horizontal,  it  is  there  superior  to  the  flexor  brevis, 
inferior  to  the  transversalis  pedis  and  peronaeus  longus  tendon;  the  lumbri- 
cales  muscles  arise  from  its  tendons. 

Tibialis  Posticus,  larger  above  than  below,  arises  from  the  posterior  and 
internal  part  of  the  fibula,  from  the  upper  part  of  the  tibia,  and  from  almost 
the  entire  length  of  the  inter-osseous  ligament ; the  fibres  descend,  and  end 
in  a strong  tendon  which  passes  along  with  that  of  the  last  muscle  behind  the 
internal  ankle,  crosses  above  that  tendon,  and  then  proceeds  obliquely  for- 
wards and  inwards,  and  is  inserted  into  a tuberosity  on  the  inferior  and 
internal  part  of  the  os  naviculare,  and  into  the  internal  cuneiform  bone  : it 
also  sends  some  fibres  to  the  cuboid  and  to  the  second  and  third  metatarsal 
bones;  a small  bony  or  cartilaginous  tubercle  is  often  found  in  this  tendon, 
near  to  its  insertion,  beneath  the  head  of  the  astragalus ; it  also  glides  over  a 
small  bursa  in  this  situation.  Use,  to  extend  the  ankle,  and  to  raise  the  inner 
edge  of  the  foot  from  the  ground ; the  upper  end  of  this  muscle  is  notched  by 
the  anterior  tibial  vessels,  a few  of  its  fibres  accompany  these  vessels  through 
the  inter -osseous  space,  and  are  attached  to  the  anterior  surface  of  the 


OR  MANUAL  OF  ANATOMY. 


155 


ligament ; in  its  coarse  down  the  leg  it  is  covered  by  the  solaeus,  and  overlapped 
by  the  flexor  communis  and  flexor  pollicis,  it  covers  the  tibia,  fibula,  and 
inter-osseous  ligament;  it  passes  beneath  the  head  of  the  astragalus,  and  sup- 
ports that  strong  fibro-cartilage,  which  extends  from  the  os  calcis  to  the  os 
naviculare,  beneath  the  head  of  the  astragalus,  which  substance  supports  a 
great  portion  of  the  weight  of  the  body  in  standing  or  in  progression. 

Flexor  Pollicis  Longus  arises  from  the  two  inferior  thirds  of  the  fibula, 
by  fleshy  fibres,  which  descends  obliquely  inwards  to  a tendon  which  passes 
behind  the  internal  malleolus  through  a groove  first  in  the  tibia,  and  next  in 
the  astragalus ; entering  the  sole  of  the  foot  this  tendon  crosses  above  the 
flexor  communis,  and  is  connected  to  it  by  a tendinous  slip,  it  then  proceeds 
forwards  and  inwards,  between  the  two  portions  of  the  flexor  pollicis  brevis, 
enters  a tendinous  sheath,  and  is  inserted  into  the  last  phalanx  of  the  great 
toe.  Use,  to  flex  this  toe,  to  extend  the  ankle  and  adduct  the  foot : this  mus- 
cle lies  to  the  fibular  side  of  the  tibialis  posticus,  between  it  and  the  peronsei 
muscles  ; as  it  passes  behind  the  internal  ankle  it  is  about  half  an  inch  behind 
the  tendons  of  the  tibialis  posticus  and  the  flexor  communis,  and  is  separated 
from  these  by  the  posterior  tibial  nerve  and  vessels. 

§ 5. — Dissection  of  the  Muscles  of  the  Foot . 

There  is  but  one  muscle  on  the  dorsum  or  on  the  upper  surface  of  the  foot, 
the  extensor  digitorum  brevis,  which  has  been  already  examined,  as  being  a 
sort  of  appendix  to,  or  continuation  of  the  long  extensors  of  the  toes  which 
arise  from  the  bones  of  the  leg.  The  integuments  and  fascia  in  the  sole  of 
the  foot  have  been  already  noticed ; the  muscles  here  are  very  numerous,  they 
may  be  divided  into  four  laminse,  these  are  tolerably  distinct  about  the  middle 
of  this  region,  but  at  either  side  this  arrangement  is  rather  artificial ; the  two 
inter-muscular  processes  of  the  plantar  fascia  also  divide  these  muscles  into 
three  compartments,  an  internal,  a middle,  and  an  external.  The  muscles 
of  the  first  or  superficial  layer,  are  the  abductor  pollicis,  flexor  digitorum  brevis, 
and  abductorminimi  digiti ; in  the  second  layer  are  the  long  flexor  tendons,  the 
accessory  muscle  and  the  lumbricales  ; the  third  layer  consists  of  the  flexor  pol- 
licis brevis,  adductor  pollicis,  transversalis  pedis,  and  flexor  minimi  digiti ; in 
the  fourth  layer,  are  the  interossei  muscles,  and  the  tendon  of  the  peronseus 
longus. 

Abductor  Pollicis,  arises  tendinous  and  fleshy  from  the  lower  and  inner 
part  of  the  os  calcis,  from  the  internal  annular  ligament,  the  plantar  aponeu- 
rosis, and  internal  inter-muscular  septum ; the  fibres  pass  forwards  and  in- 
wards, and  are  inserted  tendinous  into  the  internal  sesamoid  bone,  and  into 
the  internal  side  of  the  base  of  the  first  phalanx  of  the  great  toe.  Use  to 
separate  the  great  toe  from  the  others  ; this  muscle  is  by  some  writers  called 
the  adductor  pollicis,  its  action  being  then  referred  to  the  mesial  line  of  the 
body ; it  is  the  most  internal  of  the  plantar  muscles  and  is  superficial,  the 
fascia  covering  it  is  very  thin. 

Flexor  Digitorum  Brevis  Perforatus,  arises  from  the  inferior  and  rather 
from  the  internal  part  of  the  os  calcis,  from  the  internal  annular  ligament,  the 
plantar  aponeurosis  and  inter-muscular  septa  ; it  forms  a fleshy  mass,  which 
passing  forwards  divides  about  the  middle  of  the  foot  into  four  delicate  ten- 
dons, which  ccompany  the  flexor  longus  communis  into  the  tendinous  and 


156 


THE  DUBLIN  DISSECTOR, 


synovial  sheaths,  beneath  the  phalanges  of  the  four  outer  toes ; each  tendon  is 
slit  opposite  the  base  of  the  second  phalanx,  and  having  transmitted  the  lon» 
flexor  tendon,  this  short  tendon  is  then  folded  out  on  the  inferior  surface  of  the 
second  phalanx,  and  is  inserted  into  it,  above  the  long  flexor  tendon.  Use,  to 
assist  the  long  flexor,  to  strengthen  the  plantar  fascia,  and  to  preserve  the  arch  of 
the  foot ; this  muscle  is  immediately  above  the  strong  ceutral  portion  of  the 
plantar  fascia,  from  which  a considerable  portion  of  it  arises,  it  therefore 
always  presents  a rough  surface^when  dissected  ; it  is  beneath  the  long  flexor 
tendons,  the  accessory  muscle  and  the  lumbricales ; it  is  joined  to  the  abductor 
pollicis  posteriorly,  but  anteriorly  is  separated  from  it  by  the  tendon  of  the 
flexor  pollicis  longus ; the  fourth  or  the  external  of  its  tendons,  or  that  for 
the  little  toe  is  sometimes  wanting. 

Abductor  Minimi  Digiti,  is  situated  along  the  outer  edge  of  the  foot,  arises 
tendinous  and  fleshy  from  the  outer  side  of  the  os  calcis,  and  from  a strong 
ligament  which  extends  from  this  to  the  fifth  metatarsal  bone,  also  from  the 
base  of  the  latter,  from  the  plantar  fascia  and  its  external  inter-muscular  sep- 
tum ; inserted  tendinous  into  the  outer  side  of  the  base  of  the  first  phalanx  of 
the  little  toe,  and  into  the  adjoining  surface  of  the  metatarsal  bone.  Use,  to 
separate  the  little  toe  from  the  others,  and  to  flex  it ; this  muscle  is  also  super- 
ficial, the  fascia  covering  it  is  very  strong,  it  is  the  most  external  of  the  mus- 
cles in  this  region.  Detach  this  first  layer  of  muscle  from  their  posterior  attach- 
ments, and  throw  them  forwards  towards  the  toes ; the  tendons  of  the 
flexor  pollicis  and  communis  are  now  exposed,  also  the  accessory  muscle 
and  the  lumbricales ; all  these  constitute  the  second  layer  of  the  plantar 
muscles. 

The  tendon  of  the  flexor  longus  digitorum  communis  is  seen  passing  from 
the  inner  side  of  the  os  calcis  to  the  middle  of  the  plantar  region,  where  it  di- 
vides into  its  four  tendons,  which  have  been  already  described  as  entering  the 
sheaths  on  the  inferior  surface  of  the  four  outer  toes,  passing  through  the  slits 
in  the  tendons  of  the  flexor  brevis,  and  then  inserted  into  the  last  phalanx  of 
each  toe.  The  tendon  of  the  flexor  pollicis  longus  is  now  also  seen  passing 
above  the  former,  to  which  it  is  united  by  a tendinous  fasciculus,  and  then  pro- 
ceeding forwards  to  the  great  toe. 

Musculus  Accessorius,  or  flexor  digitorum  accessorius,  arises  fleshy  and  ten- 
dinous from  the  inferior  and  internal  part  of  the  os  calcis,  forms  a flat  and  some- 
what square  fleshy  belly,  which  proceeding  forwards,  is  inserted  into  the  upper 
and  outer  part  of  the  tendon  of  the  flexor  digitorum  longus.  just  before  it  divides. 
Use,  to  assist  the  long  flexor,  and  to  counteract  its  obliquity ; this  muscle  lies 
above  the  flexor  digitorum  brevis. 

Lumbricales  are  four  small  muscles  which  arise  tendinous  and  fleshy  from 
the  tendons  of  the  flexor  digitorum  longus ; there  is  none  for  the  great  toe ; the 
first  or  the  internal  one  is  the  largest;  these  four  muscles  proceed  forwards  along 
the  internal  edge  of  the  long  flexor  tendons,  each  ends  in  a thin  aponeurosis, 
which  is  inserted  into  the  internal  side  of  the  first  phalanx  of  the  four  lesser 
toes,  and  joins  the  tendinous  expansion  of  the  extensor  tendons  on  the  dorsum 
of  the  toes.  Use,  to  adduct  and  to  assist  in  flexing  the  four  toes,  they  may 
also  extend  their  second  and  last  phalanges.  These  muscles  are  covered  in 
the  sole  of  the  foot  by  the  superficial  layer ; their  tendinous  insertions  are 
superficial,  and  are  best  seen  on  the  dorsum  of  the  toes.  Detach  this  second 
layer  of  muscles  and  throw  it  also  forwards  towards  the  toes. 


OR  MANUAL  OF  ANATOMY. 


157 


The  third  layer  of  the  plantar  muscles  consists  of  the  flexor  pollicis  brevis, 
adductor  pollicis,  transversalis  pedis,  and  flexor  minimi  digiti. 

Flexor  Pollicis  Brevis,  narrow  posteriorily,  broad  and  notched  anteriorily ; 
arises  by  a strong  tendon  from  the  lower  and  anterior  part  of  the  os  calcis,  also 
from  the  external  cuneiform  bone,  it  forms  a fleshy  belly,  which  passes  for- 
wards and  inwards,  and  divides  into  two  short  tendons;  these  are  inserted 
into  the  sesamoid  bones  beneath  the  first  phalanx  of  the  great  toe.  Use,  to  flex 
the  first  joint  of  the  great  toe,  also  to  approximate  this  toe  to  the  others. 
This  muscle  forms  a sort  of  sheath  for  the  tendon  of  the  flexor  pollicis 
longus. 

Adductor  Pollicis,  is  situated  external  to  the  last  muscle,  or  more  in  the 
centre  of  the  foot;  it  is  also  inseparably  attached  to  it;  it  arises  tendinous  and 
fleshy  fron  the  strong  calcaneo-cuboid  ligament,  and  from  the  base  of  the 
second  and  third  metatarsal  bones,  it  passes  forwards  and  inwards,  and  is  in- 
serted along  with  the  external  portion  of  the  last  muscle  into  the  external 
sasamoid  bone.  Use,  to  draw  the  great  toe  outwards  towards  the  other  toes, 
also  to  flex  it,  so  as  to  bring  the  great  toe  beneath  the  other  toes.  By  some 
this  muscle  is  name  the  abductor  pollicis,  its  action  being  then  referred  to  the 
mesial  line. 

Tranversalis  Pedis,  arises  by  distinct  fleshy  slips  from  the  anterior  ex- 
tremities of  the  four  external  metatarsal  bones  ; the  fibres  passin wards  and  for- 
wards, converging  to  the  external  sesamoid  bone  of  the  great  toe,  into  which 
they  are  inserted  along  with  the  last  described  muscle.  Use , to  approximate 
the  toes,  and  to  contract  the  transverse  arch  of  the  foot ; beldnd  this  muscle  the 
strong  calcaneo-cuboid  ligament  is  observed,  also  the  tendon  of  the  tibialis  pos- 
ticus dividing  into  several  slips,  which  are  inserted  into  the  adjacent  bones 
and  ligaments. 

Flexor  Brevis  Minimi  Digiti,  arises  tendinous  and  fleshy  from  the  cuboid 
and  fifth  metatarsal  bone,  and  from  the  sheath  of  the  peronaeus  longus  tendon ; 
it  passes  forwards  and  outwards,  and  is  inserted  into  the  inner  side  of  the 
base  of  the  first  phalanx  of  the  little  toe.  Use,  to  flex  and  adduct  this  toe. 
This  muscle  is  connected  to  the  abductor  minimi  digiti ; it  fills,  up  the  conca- 
vity of  the  fifth  metatarsal  bone.  Detach  these  four  muscles  in  this  layer  from 
the  tarsus,  and  the  fourth  layer  will  come  into  view,  namely,  the  tendon  of  the 
peronaeus  longus  and  the  interossei  muscles ; the  former  crosses  the  foot 
obliquely  forwards  and  inwards  from  a deep  groove  in  the  cuboid,  beneath 
the  cuneiform  and  metatarsal  bones,  to  be  inserted  into  the  internal  cuneiform, 
and  into  the  base  of  the  first  and  second  metatarsal  bones  ; in  this  course  this 
strong  round  tendon  is  enclosed  in  a tendinous  sheath,  which  is  lined  by  syno- 
vial membrane,  and  is  attached  to  the  several  projections  of  the  adjoining 
bones.  Use,  to  serve  as  a strong  transverse  ligament  in  strengthening  the 
tarsus  and  metatarsus  in  that  direction  ; this  course  and  connection  of  the  ten- 
don explains  the  action  of  the  peronaeus  longus  muscle,  namely,  to  extend 
the  ankle  joint,  to  elevate  the  external  side  of  the  foot,  to  depress  its  internal 
side,  and  to  turn  the  point  of  the  foot  outwards. 

Interossei  Muscles  are  seven  in  number ; three  are  seen  in  the  sole  of  the 
foot,  and  four  on  the  dorsum ; they  fill  up  the  interstices  between  the  metatar- 
sal bones : the  three  inferior  are  named  interossei  interni  or  inferiores  ; they 
arise  tendinous  and  fleshy  from  between  the  metatarsal  bones  of  the  four 


158 


THE  DUBLIN  DISSECTOR, 


external  toes,  and  are  inserted  tendinous  into  the  inner  side  of  the  base  of  the 
first  phalanx  of  the  three  lesser  toes.  Use,  to  abduct  the  toes. 

The  first  of  the  inferior  interossei  is  situated  between  the  second  and  third 
metatarsal  bones,  it  arises  chiefly  from  the  inner  side  of  the  latter,  and  is  in- 
serted into  the  inner  side  of  the  first  phalanx  of  the  third  or  middle  toe  ; this 
may  be  named  the  adductor  me'dii  digiti ; the  second  is  between  the  third 
and  fourth  metatarsal  bones  ; arises  chiefly  from  the  inner  side  of  the  latter, 
and  is  inserted  into  the  inner  side  of  the  first  phalanx  of  the  fourth  toe,  and 
may  be  named  adductor  quarti  digiti  ; the  third  is  between  the  fourth  and 
fifth  metatarsal  bones,  arises  from  the  latter  , and  is  inserted  into  the  inner 
side  of  the  little  toe,  and  may  be  named  the  adductor  minimi  digiti. 

The  interossei  externi  or  superiores  are  four  in  number,  are  larger  than  the 
last,  and  are  seen  on  the  dorsum  or  convex  surface  of  the  foot ; they  are  bici- 
pital muscles ; the  first  is  between  the  first  and  second  metatarsal  bones  and 
may  be  named  the  adductor  digiti  secundi ; it  arises  from  the  internal  side  of 
the  second  metatarsal  bone,  and  by  a distinct  fasciculus  from  the  outer  side 
of  the  first;  these  two  origins  are  separated  by  the  deep  branch  of  the  anterior 
tibial  artery ; the  fibres  end  in  a tendon  which  is  inserted  on  the  inner  side  of 
the  base  of  the  first  phalanx  of  the  second  toe  ; it  also  joins  the  corresponding 
extensor  tendon.  Use,  to  approximate  the  second  to  the  great  toe. 

Abductor  Digiti  Secunm  is  placed  between  the  second  and  third  metatar- 
sal bones  ; arises  from  their  opposite  surfaces,  but  chiefly  from  that  of  the  for- 
mer ; the  fibres  end  in  a tendon  which  is  inserted  into  the  outer  side  of  the  first 
phalanx  of  the  second  toe.  Use,  to  separate  the  second  from  the  great  toe. 

Abductor  Digiti  Medii  is,  placed  between  the  third  and  fourth  metatarsal 
bones,  and  arises  from  their  opposite  surfaces,  but  chiefly  from  that  of  the 
third  ; the  fibres  end  in  a tendon  which  is  inserted  into  the  outer  side  of  the 
first  phalanx  of  the  third  or  middle  toe.  Use,  to  separate  the  third  toe  from 
the  first  and  second. 

Abductor  Digiti  Quarti  is  situated  between  the  fourth  and  fifth  metatar- 
sal bones  ; it  arises  from  their  opposite  surfaces,  and  is  inserted  into  the'  outer 
side  of  the  first  phalanx  of  the  fourth  toe.  Use,  to  separate  the  fourth  toe 
from  the  three  internal. 

All  the  interossei  muscles  serve  to  strengthen  the  metatarsus,  to  press  the 
metatarsal  bones  together  ; they  also  serve  to  flex  the  first  joint  of  the  four 
outer  toes,  and  may  assist  in  extending  their  last  phalanges  ; these  muscles 
can  exert  no  influence  on  the  great  toe ; there  is  only  one  muscle  between  the 
two  first  metatarsal  bones ; between  the  others  there  are  two,  therefore  there 
are  four  superior  or  dorsal  interossei  muscles,  but  three  inferior ; the  latter  are 
situated  more  in  the  concavity  of  each  metatarsal  bone  than  between  these 
bones ; the  superior  are  stronger  and  more  tendinous  than  the  inferior,  and  are 
only  partially  covered  by  the  long  and  short  extensor  tendons. 

In  dissecting  the  muscles  on  the  back  of  the  leg,  and  those  in  the  sole  of 
of  the  foot,  we  meet  the  posterior  tibial  artery  and  nerve,  and  their  principal 
branches.  The  posterior  tibial  artery  is  the  larger  branch  of  the  popliteal ; it 
descends  obliquely  inwards  beneath  the  deep  fascia  and  the  superficial 
muscles,  and  over  the  tibialis  posticus  and  flexor  communis  to  the  fossa 
between  the  heel  and  inner  ankle,  it  here  ends  in  the  two  plantar  arteries  ; in 
this  course  it  gives  off  many  muscular  branches,  also  the  peronceal  artery  ; the 


OR  MANUAL  OF  ANATOMY. 


159 


latter  arises  from  the  tibial,  about  an  inch  below  the  poplitseus ; it  descends 
obliquely  outwards  along  the  back  part  of  the  fibula  beneath  the  flexor  pollicis 
longus ; behind,  and  a little  above  the  outer  ankle,  it  divides  into  the  anterior 
and  posterior  peronaeal  arteries ; the  former  perforates  the  interosseous  space 
and  joins  the  external  malleolar  artery  ; the  latter  descends  between  the  ex- 
ternal ankle  and  the  heel,  and  is  distributed  to  the  ligaments  and  adipose 
substance  in  that  region. 

The  two  plantar  branches  of  the  posterior  tibial  artery  are  distributed  to  the 
muscles  and  integuments  of  the  foot  and  toes ; the  internal  plantar  is  the  smaller 
of  the  two,  it  supplies  the  muscles  along  the  inner  side  of  the  tarsus ; the  ex- 
ternal plantar,  the  larger  branch,  runs  across  the  foot  obliquely  outwards, 
towards  the  fifth  metatarsal  bone,  between  the  first  and  second  layers  of 
plantar  muscles ; from  the  little  toe  it  next  runs  obliquely  forwards  and  inwards, 
towards  the  first  metatarsal  bone,  above  the  second  layer  of  the  plantar  mus- 
cles, and  between  the  first  and  second  metatarsal  bones  it  joins  the  deep 
branch  of  the  anterior  tibial  artery,  and  thus  forms  the  great  plantar  arch  of 
arteries,  from  the  convexity  of  which  proceed  the  digital  arteries,  to  supply  the 
toes.  (See  Anatomy  of  the  Vascular  System.)  The  posterior  tibial  artery  and 
its  several  branches  are  accompanied  by  corresponding  veins,  all  of  which 
end  in  the  popliteal  vein.  The  posterior  tibial  nerve  is  the  principal  branch 
of  the  sciatic,  it  accompanies  the  posterior  tibial  artery,  at  first  lying  to  its 
tibial,  afterwards  to  its  fibular  side;  in  this  course  it  sends  off  several  small 
branches  to  the  deep  and  superficial  muscles  of  the  leg,  and  between  the  heel 
and  ankle  it  divides  into  the  two  plantar  nerves,  which  take  the  course  of  the 
corresponding  arteries.  In  this  internal  malleolar  region,  when  the  integu- 
ments, fascia  and  internal  annular  ligament  are  removed,  we  find  the  three 
tendons,  the  posterior  tibial  nerves  and  vessels  to  have  the  following  relation 
to  each  other,  the  tibialis  posticus  and  flexor  communis  tendons  are  bound 
close  to  the  ankle,  about  half  an  inch  behind  these  is  the  posterior,  tibial  ar- 
tery accompanied  by  two  veins,  the  nerve  is  a little  nearer  to  the  heel,  and 
the  tendon  of  the  flexor  pollicis  lies  about  half  an  inch  nearer  to  the  latter. 


PART  II. 


CHAPTER  I. 

ANATOMY  OF  THE  NERVOUS  SYSTEM. 

THIS  SYSTEM  MAY'  BE  DIVIDED  INTO  FOUR  PRINCIPAL  PARTS,  THE  BRAIN,  THE 
SPINAL  CORD,  THE  NERVES,  AND  THE  GANGLIONS. 

§ 1. — Dissection  of  the  Brain. 

The  brain  is  subdivided  into  three  portions,  cerebrum,  cerebellum,  and 
medulla  oblongata ; these  are,  however,  so  intimately  connected,  that  it  is 
difficult  to  mark  the  exact  limits  of  each. 

Divide  the  scalp  from  one  ear  across  the  vertex  to  the  other  ; reflect  one  flap 
over  the  face,  the  other  over  the  back  of  the  neck ; make  a circular  cut  with  a 
sawthrough  the  cranium  on  a level  with  the  cartilage  of  the  ear  on  each  side, 
anteriorly  about  an  inch  above  the  superciliary  arches,  and  posteriori  v a little 
below  the  tubercle  of  the  os  occipitis.  It  is  only  necessary  to  sawthrough. 
the  outer  table  of  the  bones,  the  elevator,  or  a few  smart  strokes  with  the  claw 
of  the  hammer  will  then  suffice  to  crack  the  internal  table  (indeed  the  cranium 
may  be  opened  by  the  hammer  alone ; this  plan,  however,  injures  the  bones  so 
much  as  to  leave  them  of  little  use  to  the  student).  The  calvarium  being  now 
forcibly  torn  away,  the  dura  mater  is  exposed;  the  latter,  in  some  subjects, 
adheres  so  closely  to  the  bone  as  to  be  torn  along  with  it ; this  accident  will 
injure  the  brain,  and  may  be  avoided  by  introducing  the  handle  of  the  knife 
or  any  blunt  instrument  between  the  membrane  and  the  bone  as  you  graduallv 
raise  off  the  latter.  If  the  student  can  procure  two  subjects  it  will  facilitate 
his  study  to  examine  the  brain  of  both  at  the  same  time ; in  one  dissect  the 
parts  in  situ,  and  from  the  other  remove  the  brain  in  the  following  manner : 
commencing  anteriorly,  gently  raise  it  from  the  base  of  the  skull,  divide  each 
nerve  and  vessel  in  succession  from  before  backwards  close  to  the  bone,  dis- 
locate the  pituitary  gland  from  the  sella  turcica,  and  cut  through  the  tentorium ; 
next  divide  the  spinal  cord  as  low  down  in  the  neck  as  you  can  pass  the  knife 
through  the  foramen  magnum  ; then  place  the  brain,  its  base  upwards,  in  a 
shallow  basin ; thus  the  different  surfaces  and  structures  of  the  brain,  as  also 
the  several  processes  and  sinuses  of  the  dura  mater  can  be  examined  in  con- 
tinuation with  each  other. 

The  membranes  covering  the  brain  are  three,  the  dura  mater,  arachnoid 
membrane,  and  pia  mater ; the  first  may  be  termed  the  fibrous,  the  second  the 
serous,  and  the  third  the  vascular  coat ; these  three  tunics  also  extend  through 
the  spinal  canal  and  cover  the  spinal  cord.  The  dura  mater  is  a fibro-serous 

160 


OR  MANUAL  OF  ANATOMY. 


161 


membrane,  of  considerable  strength,  and  of  a whitish  color,  sometimes  it  has 
a bluish  tint;  the  external  surface  adheres  intimately  to  the  bones;  it  now- 
presents  a rough  surface,  and  several  red  spots,  particularly  in  the  course  of 
the  sutures;  these  are  owing  to  the  ruptured  vessels  which  passed  from  the 
dura  mater  to  the  bone,  the  former  being  the  internal  periosteum  to  the  latter; 
in  the  young  subject  the  connection  between  the  two  is  so  close  and  vascular, 
that  is  very  difficult  to  separate  them  in  the  recent  state,  and  when  this  is 
effected,  numerous  bloody  dots  are  observable  on  each;  this  membrane  is 
more  intimately  attached  to  the  bones  at  the  base  of  the  cranium  than  in  any 
other  situation,  it  there  sends  small  processes  through  the  several  foramina, 
some  of  these  accompany  the  vessels  and  nerves,  and  are  gradually  lost  on 
them,  others  become  continuous  with  the  periosteum ; the  most  remarkable  of 
these  processes,  next  to  that  which  is  continued  along  the  spinal  canal,  is  one 
which  passes  through  the  foramen  lacerum  orbitale,  and  joins  the  periosteum 
in  the  orbit,  and  another  which  surrounds  the  optic  nerve,  and  is  united  to  the 
sclerotic  coat  of  the  eye.  Several  small  arteries  ramify  on  this  membrane, 
between  it  and  the  bones  of  the  cranium,  anteriorly  these  are  derived  from  the 
opthalmic  and  internal  carotid  vessels  ; the  middle  artery  of  the  dura  mater 
is  the  largest,  this  is  a branch  of  the  internal  maxillary,  it  enters  the  base  of 
the  cranium,  through  the  spinous  hole  in  the  sphenoid  bone,  passes  forwards 
and  upwards  above  the  temporal  and  sphenoid  bones,  then  ascends  obliquely 
backwards  on  the  inner  surface  of  the  parietal  bone,  the  anterior  and  inferior 
angle  of  which  it  grooves  very  deeply ; posteriorly  the  dura  mater  receives 
several  small  arteries,  viz.  branches  from  the  occipital,  pharyngeal,  and  verte- 
bral arteries ; these  vessels  of  the  dura  mater  also  supply  the  superincumbent 
bones  with  blood.  Cut  through  this  membrane  parallel  to  the  edge  of  the 
cranium,  raise  it  from  each  side  of  the  brain  towards  the  vertex,  leaving  a 
small  portion  of  it  in  the  mesial  line,  both  before  and  behind  undivided;  the 
internal  surface  is  now  seen  to  be  smooth  and  polished,  and  moistened  with  a 
fine  serous  exhalation ; this  surface  is  the  reflected  or  the  parietal  layer  of  the 
arachnoid  membrane  (to  be  examined  presently),  it  adheres  so  closely  to  the 
dura  mater  that  it  is  difficult  to  separate  them  for  any  extent,  unless  pre- 
viously macerated. 

From  the  internal  surface  of  the  dura  mater,  folds  or  processes  extend  into 
the  cranium,  which  divide  this  cavity  into  several  compartments,  and  support 
and  separate  different  portions  of  the  brain;  these  processes  are  the  falx  cere- 
bri, tentorium  cerebelli  and  falx  cerebelli.  The  falx  cerebri  is  exposed  by 
gently  separating  one  hemisphere  of  the  brain  from  the  other  ; it  commences 
narrow  at  the  crista  galli  and  middle  ridge  of  the  ethmoid  bone,  thence  it 
ascends  in  the  median  line,  and  passing  backwards,  ends  by  being  continued 
into  the  tentorium;  the  convex  edge  of  this  process  corresponds  to  the  middle 
ridge  or  groove  of  the  os  frontis,  to  the  sagittal  edge  of  the  two  parietal  bones, 
and  to  the  perpendicular  ridge  of  the  occipital ; the  great  longitudinal  sinus  is 
enclosed  between  the  layers  of  this  process,  the  whole  extent  of  this  edge ; the 
concave  or  inferior  border  of  the  falx  corresponds  to  the  middle  line  of  the 
corpus  callosum,  from  which  it  is  but  a very  short  distance ; the  inferior  or 
lesser  longitudinal  sinus  is  enclosed  in  this  ridge ; the  falx  divides  the  cavity 
of  the  cranium  in  the  middle  line,  it  separates  the  hemispheres  of  the  cere- 
brum, and  in  different  positions  of  the  body  supports  the  weight  of  each ; in 
21 


162 


THE  DUBLIN  DISSECTOR, 


old  subjects  it  is  often  cribriform,  and  in  some  it  is  partly  converted  into  bone. 
The  tentorium  cerebelli  extends  in  somewhat  a horizontal  direction  across  the 
posterior  part  of  the  cranium;  it  may  be  seen  by  gently  raising  the  back  part 
of  either  hemisphere  of  the  brain ; the  convex  edge  of  this  fold  is  attached  to 
the  transverse  ridge  of  the  occipital  bone,  to  the  inferior  angle  of  the  parietal 
bones,  to  the  superior  angle  of  the  petrous  "bones,  and  to  the  posterior  clinoid 
processes  of  the  sphenoid  ; over  this  last  attachment,  the  concave  edge  of  the 
tentorium  glides  and  is  inserted  into  the  anterior  clinoid  processes ; the  tento- 
rium is  raised  and  held  in  a state  of  tension  along  the  median  line  by  the  falx, 
its  inferior  surface  is  concave ; anteriorly  it  presents  a large  oval  opening, 
which  is  on  a plane  anterior  to  the  foramen  magnum,  this  is  filed  by  the  supe- 
rior vermiform  process  of  the  cerebellum,  the  crura  cerebri  and  the  pons 
varolii;  along  the  convex  edge  of  the  tentorium,  between  its  layers  are  two 
sinuses  on  each  side,  the  great  lateral  and  the  superior  petrous,  in  the  median 
line  also  is  another  called  the  straight  sinus,  which  extends  along  the  base  of 
the  falx  ; the  tentorium  serves  to  support  the  weight  of  the  cerebrum  off  the 
cerebellum. 

Th  efalx  cerebelli  is  seen  when  the  brain  is  removed;  it  is  a small  but  thick 
process  of  little  importance,  the  base  is  superiorly  attached  to  the  tentorium, 
the  apex  inferiorly,  at  the  foramen  magnum  ; its  convex  edge  adheres  to  the 
occipital  spine,  and  contains  between  its  layers  the  occipital  sinuses  ; its  con- 
cave edge  separates  the  hemispheres  of  the  cerebellum  ; this  process  serves  to 
retain  the  tentorium  and  falx  cerebri  in  a state  of  tension.  Attached  to  the 
lesser  wing  of  the  sphenoid  bone  on  each  side,  is  a slight  fold  of  dura  mater, 
termed  the  sphenoidal  fold  ; these  serve  to  increase  the  surface  of  the  anterior 
fossae  of  the  base  of  the  cranium,  and  correspond  to  the  fissures  of  Sylvius  at 
the  base  of  the  brain.  The  uses  of  the  dura  mater  are,  first  to  serve  as  a peri- 
osteum ; second,  to  cover  the  brain ; third  by  its  processes  to  separate  and 
support  the  different  parts  of  this  organ  ; fourth,  to  form  sheaths  for  several  of 
the  nerves  as  they  leave  the  cranium;  and  fifth,  to  form  the  sinuses  which  may 
be  next  examined. 

The  sinuses  correspond  to  the  veins,  or  in  fact  they  are  veins  enclosed  be- 
tween the  laminae  of  the  dura  mater,  which  thus  retain  them  in  their  situation, 
and  enable  them  to  resist  distension ; the  sinuses  are,  the  superior  and  inferior 
longitudinal,  the  straight,  the  right  and  left  lateral,  the  superior  and  inferior 
petrous,  the  right  and  left  cavernous,  the  circular,  the  transverse,  the  occipital 
and  the  torcular  Herophili.  The  superior  longitudinal  sinus  commences  at 
the  crista  galli,  either  in  a small  cul  de  sac,  or  by  a small  vein  from  the  nose ; 
it  extends  upwards  and  backwards  along  the  median  line,  increasing  in  size, 
and  opposite  the  tubercle  of  the  os  occipitis  it  divides  into  the  right  and  left 
lateral  sinuses,  the  right  branch  being  in  general  the  larger;  with  the  scissors 
lay  open  this  sinus  through  its  whole  length;  it  appears  somewhat  triangular, 
lined  by  a smooth  fine  membrane,  which  is  continuous  with  that  lining  the 
venous  system;  in  general  it  is  usually  dilated  near  the  vertex;  small  white 
fibrous  bands  cross  it  in  many  places  ; these  have  an  imperfect  resemblance 
to  the  valves  of  veins,  and  may  serve  to  resist  distension  of  the  sinus  ; they 
have  been  named  cor  dee  Willisii ; about  the  middle  of  this  sinus  there  are  in 
general  a number  of  small  whitish  bodies,  sometimes  lying  singly,  but  more 
frequently  in  clusters,  near  the  openings  of  some  of  the  veins  in  the  sinus. 


OR  MANUAL  OF  ANATOMY. 


163 


these  are  termed  glandulm  Pacchioni;  their  size,  number,  and  appearance, 
differ  considerably  in  different  subjects;  in  the  very  young  there  are  few,  if 
any;  in  the  old,  they  are  most  numerous  ; they  are  found  in  three  situations, 
in  the  cavity  of  the  sinus,  external  to  the  dura  mater,  or  internal  to  it;  the 
first  are  termed  the  glandulse  mediae,  the  second  the  externae,  and  the  third 
the  internas ; their  use  or  structure  is  unknown,  most  probably  they  are  by  no 
means  allied  to  the  glandular  system.  The  longitudinal  sinus,  like  all  the 
other  sinuses,  consists  of  two  tunics,  the  internal  or  the  venous  membrane, 
and  the  external  or  fibrous  coat  derived  from  the  dura  mater;  this  membrane 
is  described  as  dividing  into  two  layers  on  either  side  of  the  cavity;  one  con- 
tinues to  adhere  to  the  bone,  and  the  other  laminae  descend  on  either  side  of 
the  sinus,  and  unite  in  the  falx  ; the  base  of  the  triangular  cavity  thus  formed 
is  towards  the  bone,  the  apex  towards  the  falx;  in  addition  to  many  small 
veins,  from  the  bones  and  from  the  dura  mater,  this  sinus  receives  near  the 
vertex  eight  or  ten  large  veins  from  the  upper  surface  of  each  hemisphere  of 
the  brain,  these  run  obliquely  forwards  between  the  coats  of  the  sinus,  some 
for  an  inch,  others  for  less,  before  they  open  into  the  cavity,  and  just  as  they 
are  terminating,  they  turn  slightly,  so  that  their  mouths  look  inwards,  or  to- 
wards those  of  the  opposite  side ; all  the  veins  which  enter  the  sinus  do  not 
take  the  oblique  course  now  described,  and  which  is  most  probably  designed 
to  impede  the  reflux  of  the  blood  from  the  sinus  into  the  cerebral  veins.  The 
inferior  longitudinal  sinus  is  not  always  present,  it  resembles  a small  vein 
enclosed  in  the  lower  edge  of  the  falx  near  its  base,  it  receives  small  veins 
from  the  corpus  callosum,  and  ends  in  the  following;  the  straight  sinus  is 
situated  in  the  median  line,  enclosed  between  the  laminae  of  the  base  of  the 
falx  and  above  the  tentorium,  it  receives  the  blood  from  the  lateral  ventricles 
returned  by  the  two  venae  Galeni ; this  sinus  proceeds  backwards  and  down- 
wards, and  ends  in  the  confluence  of  the  two  lateral  and  longitudinal  sinuses ; 
it  presents  internally  the  same  fibrous  appearance  as  the  great  longitudinal 
sinus.  The  lateral  are  the  largest  sinuses,  of  somewhat  an  elliptical  figure, 
each  proceeds  at  first  horizontally  outwards  and  forwards,  enclosed  between 
the  laminae  of  the  tentorium,  in  a groove  in  the  occipital  bone,  and  in  the 
inferior  angle  of  the  parietal;  it  then  descends  inwards  along  the  mastoid 
portion  of  the  temporal  bone,  and  again  indenting  the  occipital,  it  turns  for- 
wards, and  passing  through  the  foramen  lacerum  posterius,  ends  in  the  internal 
jugular  vein;  each  lateral  sinus  receives  several  small  veins  from  the  poste- 
rior lobes  of  the  cerebrum  and  from  the  cerebellum ; these  enter  the  sinus 
from  without  inwards,  contrary  to  the  current  in  the  sinus  ; through  each  of 
these  sinuses  all  the  blood  is  returned  from  the  cranium  to  the  general  sys- 
tem ; there  are  seldom  any  transverse  bands  or  glandulae  Pacchioni  in  these 
sinuses.  The  following  sinuses  are  situated  on  the  base  of  the  cranium.  The 
cavernous  sinus  on  each  side  extends  from  the  anterior  clinoid  process  to  the 
point  of  the  petrous  bone  along  the  side  of  the  body  of  the  sphenoid  ; the  dura 
mater  in  this  region  divides  into  two  layers,  one  very  thin  adheres  to  the  irre- 
gular bony  surface  which  bounds  this  cavity,  the  other  much  more  dense  is 
reflected  over  this  space,  and  contains  between  its  laminae  the  third  and  fourth 
nerve,  and  the  first  part  of  the  fifth  ; the  ophthalmic  vein  opens  into  the  fore- 
part of  this  sinus,  and  the  two  petrosal  sinuses  lead  from  it  posteriorly  to  the 
lateral  sinus ; this  sinus  is  intersected  by  tendinous  bands,  and  presents  rather 


164 


THE  DUBLIN  DISSECTOR, 


a cellular  or  spongy  appearance  like  the  corpus  cavernosum  penis ; the  internal 
carotid  artery  and  the  sixth  or  abducens  nerve  pass  through  the  cavity  of  this 
sinus,  also  several  small  branches  from  the  sympathetic ; the  venous  mem- 
brane, however,  is  reflected  around  each,  so  as  to  separate  them  from  the 
blood;  the  cavernous  sinuses  communicate  through  the  following;  the  circvlar 
sinus  consists  of  two  small  veins,  which  lead  from  one  cavernous  sinus  to  the 
other,  the  anterior  is  beneath  the  optic  commissure,  and  before  the  pituitary 
gland  ; the  posterior  is  behind  and  rather  below  that  body.  The  petrosal 
sinuses  are  four  in  number,  two  on  each  side,  the  superior  and  inferior ; they 
each  lead  from  the  cavernous  sinuses  backwards,  the  former  along  the  upper 
edge  of  the  petrous  bone,  to  the  lateral  sinuses  opposite  the  inferior  angle  of 
the  parietal  bone ; the  inferior  petrous  sinus  leads  downwards  and  backwards, 
over  the  suture  between  the  petrous  and  occipital  bones,  and  ends  in  the  lateral 
sinus  near  its  termination.  The  transverse  sinus  leads  from  oue  inferior 
petrosal  sinus  to  the  other,  across  the  cuneiform  process  of  the  occipital  bone. 
The  occipital  sinuses  are  two  small  canals  contained  in  the  falx  cerebelli; 
they  receive  veins  from  the  cerebellum,  and  sometimes  from  the  vertebral 
canal,  and  open  into  the  torcular  Herophili ; these  sinuses  sometimes  extend 
along  each  side  of  the  foramen  magnum,  and  communicate  with  the  lateral 
sinuses;  the  occipital  sinuses  are  often  wanting.  • The  torculi  Herophili  is  a 
sort  of  common  reservoir  in  which  several  sinuses  end  ; it  is  situated  opposite 
the  tuberosity  of  the  occipital  bone,  and  enclosed  between  the  layers  of  the 
falx  and  tentorium  ; it  is  somewhat  oval,  and  presents  six  openings,  viz.  the 
lateral  sinus  on  each  side ; the  longitudinal  sinus  above,  the  straight  sinus 
before,  and  the  occipital  sinuses  below. 

The  second  covering  of  the  brain  is  a serous  membrane,  the  arachnoid,  so 
fine  and  delicate  that  in  some  situations  it  is  difficult  to  demonstrate  it;  be- 
tween the  convolutions  of  the  brain  it  can  be  raised  from  the  pia  mater,  which 
sinks  into  the  fissures  between  these ; and  a little  air  forced  between  these 
membranes  will  separate  them  for  some  distance,  and  will  raise  the  arachnoid 
membrane  in  a vesicular  form ; on  the  base  of  the  brain,  and  in  the  spinal 
canal,  it  is  stronger,  and  can  be  distinctly  detached  from  the  subjacent  mem- 
brane. The  arachnoid  membrane  covers  the  wrhole  surface  of  the  brain,  and 
is  thence  reflected  to  the  dura  mater,  which  it  lines  throughout,  except  at  the 
sella  turcica,  where  the  pituitary  gland  intervenes  between  these  membranes; 
from  the  surface  of  the  brain  it  is  reflected  on  the  dura  mater  in  several  situa- 
tions, viz.  superiorly,  as  the  veins  enter  the  longitudinal  sinus,  this  membrane 
accompanies  them  from  the  brain  to  the  sinus,  it  is  then  reflected  to  the  inner 
surface  of  the  dura  mater:  interiorly,  also,  it  surrounds  the  nerves  in  their 
course  from  the  brain  to  the  foramina,  through  which  they  pass,  and  is  then 
reflected  on  the  dura  mater,  the  latter  membrane  being  really  perforated  and 
continued  for  a short  distance  around  each  nerve,  whereas  the  arachnoid  mem- 
brane forms  a cul  de  sac  at  the  exit  of  each ; thus  the  arachnoid  membrane, 
like  all  serous  membranes,  forms  a shut  sac,  one  side  or  layer  of  it  (the  parie- 
tal) adhering  to  the  dura  mater;  the  other  (the  visceral)  covering  the  brain 
and  extending  from  one  eminence  to  another,  without  penetrating  between 
them;  it  is  smooth,  polished,  and  transparent,  without  any  distinct  vessels : 
it  exhales  and  again  absorbs  a fine  serous  halitus  -which  allows  the  opposed 
surfaces  to  move  against  each  other  without  friction ; this  membrane  is  also 


OR  MANUAL  OF  ANATOMY. 


165 


continued  into  the  cavities  or  ventricles  of  the  brain,  and  gives  to  them  a 
smooth  lining.  To  see  this  process  ot  the  arachnoid  membrane,  separate 
gently  the  posterior  lobes  of  the  cerebrum,  divide  the  falx,  and  at  the  anterior 
edge  of  the  tentorium  the  two  venae  Galeni  will  be  seen  entering  the  straight 
sinus;  these  veins  are  surrounded  by  the  serous  membrane;  press  these 
gently  to  one  side,  and  underneath  them  a small  round  hole  or  canal  may  be 
observed,  leading  forwards  below  these  veins,  and  above  the  pineal  gland,  and 
opening  into  the  back  part  of  the  third  ventricle ; this  canal  is  lined  by  the 
arachnoid  membrane,  which  is  continued  from  that  on  the  surface  of  the  brain, 
and  expands  within  the  ventricles,  so  as  to  coverall  the  inequalities  observed 
within  them;  this  arachnoid  canal,  or  the  canal  of  Bichat,  will  be  noticed 
again  in  the  examination  of  the  ventricles.  The  third  tunic  of  the  brain  is 
the  vascular  coat,  or  the  pia  mater,  of  a very  soft  and  delicate  structure, 
loaded  with  numerous  fine  vessels;  it  adheres  to  the  whole  surface  of  the 
brain,  and  following  every  involution  of  its  surface,  it  is  intimately  united 
with  its  substance  by  numerous  shreds  and  vessels,  which  admit  of  being 
drawn  out  like  fine  threads  ; on  the  convolutions  of  the  brain  it  is  inseparably 
connected  to  the  arachnoid  membrane,  but  in  most  other  situations,  particu- 
larly at  the  base  of  the  brain,  they  are  but  loosely  united  to  each  other.  The 
pia  mater  is  also  prolonged  into  the  lateral  ventricles,  through  an  extensive 
fissure,  which  will  be  seen  in  the  dissection  of  the  brain  between  the  fornix 
and  the  corpus  callosum  above,  and  the  tubercula  quadrigemina  and  pons 
Varolii  below;  this  fissure  descends  obliquely  forwards  on  each  side  into  the 
inferior  cornu  of  each  lateral  ventricle  between  the  optic  thalamus  and  the 
hippocampus  major;  through  these  lateral  prolongations  of  this  fissure,  a pro- 
cess of  the  pia  mater  enters,  termed  the  choroid  plexus,  and  through  the  cen- 
tral or  transverse  portion  of  it,  another  process,  termed  the  choroid  membrane 
or  velum  interpositum;  these  processes  are  covered  by  the  arachnoid  mem- 
brane, and  are  all  connected  together,  as  will  be  seen  in  the  dissection  of  the 
ventricles;  this  great  fissure  in  the  brain  is  closed  every  where  by  the  arach- 
noid membrane  on  the  surface  of  the  brain,  except  at  the  foramen  of  Bichat. 
The  use  of  the  pia  mater  is  to  form  an  exact  capsule  for  the  brain,  also  an 
extensive  surface,  on  which  the  vessels  divide  minutely,  and  are  probably 
arranged  in  some  peculiar  manner,  previous  to  their  penetrating  the  substance 
of  the  brain. 

There  are  two  modes  of  dissecting  the  brain ; first,  by  removing  it  in  suc- 
cessive slices  from  above  downwards ; and  secondly,  from  below  upwards ; 
the  first  plan  is  best  adapted  for  studying  the  relative  anatomy  of  the  differ- 
ent parts  of  the  brain,  or  for  examining  this  organ  pathologically;  the  second 
for  unravelling  its  structure ; the  student  should  practise  both,  and  first,  that 
from  above  downwards. 

DISSECTION  OF  THE  CEREBRUM. 

The  Cerebrum  is  the  largest  part  of  the  brain  of  an  oval  figure,  the  larger 
end  posteriorly,  a little  flattened  on  the  sides,  convex  above,  and  divided  into 
two  equal  portions,  the  right  and  left  hemispheres,  by  a deep  fissure  which 
extends  along  the  median  line ; this  fissure  is  continued  before  and  behind 
through  the  entire  depth  of  the  cerebrum,  but  in  the  middle  it  is  bounded 


166 


THE  DUBLIN  DISSECTOR, 


below  by  the  corpus  callosum ; it  contains  the  falx  cerebri  and  the  arteries  of 
the  corpus  callosum;  each  hemisphere  is  convex  superiorly  and  externally, 
and  flat  internally,  or  towards  the  falx,  inferiorly  very  irregular  and  uneven ; 
the  surface  of  each  hemisphere  is  every  where  marked  by  a number  of  emi- 
nences termed  the  convolutions  of  the  brain  ; these  are  of  various  size  and 
shape,  and  are  somewhat  convoluted  like  the  intestines ; their  round  edges  are 
separated  by  fissures  which  are  closed  by  the  arachnoid  membrane;  these  fis- 
sures are  nearly  an  inch  deep  ; they  take  different  directions,  serpentine,  lon- 
gitudinal, and  oblique;  if  a section  of  the  cerebrum  be  made,  these  fissures 
will  be  found  to  be  only  involutions  of  the  cineritious  substance  covering  the 
brain  ; each  fissure  therefore  is  only  a continuation  of  the  surface,  and  is 
covered  throughout  by  the  pia  mater. 

The  cerebrum,  on  its  inferior  surface,  is  also  divided  into  the  two  hemispheres 
by  the  great  median  fissure  at  each  extremity,  and  in  the  centre  by  a depres- 
sion containing  several  substances  ; each  hemisphere  inferiorly  is  divided  into 
three  lobes,  the  anterior,  small,  triangular,  flat,  or  a little  concave,  rests  on 
the  roof  of  the  orbit,  presents  a deep  groove  which  lodges  the  olfactory  nerve  ; 
the  middle  lobe  is  prominent,  round,  and  deep,  fills  up  the  middle  fossa  in 
the  base  of  the  cranium,  and  is  separated  from  the  anterior  lobe  by  a deep  fis- 
sure, ( fissuru  Sylvii)  which  ascends  obliquely  outwards  and  backwards;  this 
fissure  corresponds  to  the  sphenoidal  fold  of  the  dura  mater,  and  to  the  lesser 
wing  of  the  sphenoid  bone  ; the  bfain  above  it  is  perforated  by  a number  of 
small  holes  for  the  entrance  of  vessels  {pars perforee  externe)  ; this  fissure  con- 
tains the  middle  artery  of  the  brain,  and  one  origin  of  the  olfactory  nerve. 

The  posterior  lobe  rests  on  the  tentorium,  and  is  separated  from  the  middle 
only  by  a slight  excavation  ; between  the  hemispheres  we  observe,  immediately 
behind  the  anterior  extremity  of  the  median  fissure,  the  lower  end  of  the  cor- 
pus callosum  ; posterior  to  this,  and  connected  to  it  is  the  commissure  of  the 
optic  nerves  ; behind  this  is  a soft  grey  substance,  the  tuber  cinereum  ; this  is 
connected  anteriorly  to  these  nerves,  and  posteriority  to  two  small  white  bodies 
termed  the  corpora  mamillaria  or  albicantia ; these  are  about  the  size  of  small 
peas,  situated  behind  the  tuber  cinereum,  and  attached  by  it  to  each  other; 
they  are  gray  internally,  although  white  externally,  the  anterior  pillars  of  the 
fornix  terminate  in  these.  From  the  centre  of  the  tuber  cineruma  thin  conical 
tube  of  a reddish  color  descends,  the  infundibulum ; this  passes  behind  and 
rather  beneath  the  commissure  of  the  optic  nerves;  it  terminates  on  the  sur- 
face of  the  pituitary  gland  ; it  is  surrounded  bv  arachnoid  membrane;  it  is  not 
pervious  inferiorly ; above  it  communicates  with  the  third  ventricle.  The  pitui- 
tary body  is  placed  in  the  sella  turcica  between  the  dura  mater  and  arach- 
noid membrane;  transverselv  oval,  composed  anteriorly  of  a yellowish  sub- 
stance, which  is  notched  before,  and  convex  behind  like  a kidney,  and  pos- 
teriorly of  a whitish  semi-fluid  or  pulpy  substance.  Behind  the  corpora  albi- 
cantia, we  next  observe  a small  triangular  depression,  closed  above  by  a thin 
plate  which  forms  the  posterior  part  of  the  floor  of  the  third  ventricle  ; this  is 
the  middle  perforated  plate  of  the  brain  ; on  either  side  of  this  is  the  crus  cere- 
bri, connecting  the  cerebrum  to  the  pons  Varolii,  which  last  is  situated  in  the 
median  line  behind  the  last  described  substances  ; behind  the  pons  is  the  pos- 
terior extremity  of  the  corpus  calosum  and  between  these  eminences  is  the 
great  transverse  fissure  which  transmits  the  pia  mater  into  the  ventricles,  and 


OR  MANUAL  OF  ANATOMY. 


167 


which  also  contains  the  arachnoid  canal  and  the  pineal  gland  ; behind  this  we 
observe,  lastly,  the  posterior  extremity  of  the  median  fissure  separating  the 
posterior  lobes  of  the  cerebrum. 

Cut  off  the  upper  part  of  one  hemisphere  nearly  on  a level  with  the  corpus 
callosum,  the  appearance  now  presented  is  termed  the  centrum  ovale  minus,  a 
mass  of  white  substance  surrounded  by  the  irregularly  undulating  line  of  gray 
substance  ; a small  cavity  or  fissure  may  now  also  be  observed  between  the 
corpus  callosum  and  the  lower  and  internal  margin  of  each  hemisphere:  next 
slice  off  both  hemispheres  on  a level  with  the  corpus  collosuin,  and  the  centrum 
magnum  ovale  is  presented,  that  is,  a line  of  gray  substance  surrounding  the 
central  massof  white  substance.  The  gray  or  cortical  or  cineritious  substance 
of  the  brain  is  soft  and  pulpy,  and  more  vascular  than  the  white;  on  the  sur- 
face of  the  cerebrum  it  is  about  the  eighth  of  an  inch  in  thickness;  in  other 
situations  it  is  placed  in  considerable  masses,  and  covered  by  the  white  sub- 
stance ; the  shade  of  its  color  differs  in  different  parts  of  the  brain,  and  in  dif- 
ferent subjects : in  the  child  it  is  reddish,  in  the  old  it  is  grey  or  ashy.  It  con- 
sists of  a number  of  very  minute  globules,  connected  together  by  the  pia  mater 
and  vessels.  The  white  or  medullary  substance  is  more  firm,  and  when  fresh 
has  some  elasticity,  and  in  many  parts  appears  distinctly  fibrous  ; its  divided 
surface  appears  dotted  with  red  spots ; these  are  the  divided  vessels,  they  vary 
in  number  and  size  in  different  subjects  ; in  a very  fresh  brain,  when  a sec- 
tion has  been  made  of  this  wlfite  substance,  it  will,  by  its  elasticity,  force  the 
blood  to  exude  out  for  some  little  time  in  small  drops  from  the  divided  vessels. 
The  corpus  calosum  is  now  seen  in  the  median  line  of  the  cerebrum,  but  nearer 
the  frontal  than  the  occipital  bone,  between  three  or  four  inches  long,  convex, 
white,  marked  by  two  or  three  raised  longitudinal  lines  close  and  nearly  pa- 
rallel to  each  other,  ( the  raphe,)  from  these  several  transverse  lines  pass  to 
either  side  ; its  posterior  end  broad,  round,  and  a little  concave,  is  bent  down- 
wards,  and  is  continuous  on  either  side  with  the  fornix  and  the  hippocampi ; 
its  anterior  end  is  also  round,  and  bent  downwards  and  backwards,  is  conti- 
nued on  each  side  into  the  anterior  lobes,  and  in  the  middle  it  joins  the  tuber 
cinereum  and  the  optic  commissure;  the  corpus  callosum  connects  the  white 
fibrous  substance  of  the  hemispheres,  and  is  therefore  properly  called  the  great 
commissure  of  the  cerebrum  ; it  covers  the  lateral  ventricles,  the  septum  luci- 
dum,  and  the  fornix.  Divide  this  substance  at  a little  distance  from  either 
side  of  the  raphe,  the  lateral  ventricles  will  be  opened,  press  the  middle  por- 
tion of  the  corpus  callosum  to  one  side,  and  the  septum  lucidum  may  be  seen 
descending  in  the  median  line  from  it  to  the  upper  surface  of  the  fornix.  The 
septum  lucidum  separates  the  two  lateral  ventricles,  triangular,  the  apex  be- 
hind, the  base  before,  the  upper  end  connected  to  the  corpus  callosum ; the 
lower  edge  to  the  fornix  posteriorly,  and  anteriorly  to  the  inferior  curved  por- 
tion of  the  corpus  callosum ; it  consists  of  four  laminae  two  on  each  side,  gray 
externally,  white  internally;  between  the  white  laminae  a small  cavity  exists 
termed  the  fifth  ventricle.  This  cavity  is  naturally  closed,  but  when  the  corpus 
callosum  is  divided  transversely,  and  the  anterior  portion  raised  forwards,  the 
laminae  of  the  septum  separate,  and  this  cavity  becomes  distinct;  it  is  larger 
in  the  child,  but  is  very  irregular  in  size,  and  even  in  existence  in  different 
subjects;  the  septum  lucidum  appears  to  be  formed  by  a lamina  descending 
from  each  side  of  the  raphe  of  the  corpus  callosum  to  the  fornix,  some  gray  matter 


168 


THE  DUBLIN  DISSECTOR, 


superadded.  Divide  transversely  the  septum  lucidum  and  corpus  callosum, 
raise  forwards  the  anterior  portion  of  the  latter,  and  backwards  its  posterior 
part ; it  will  now  be  seen  that  this  substance  is  united  to  the  fornix  posteriorly, 
but  is  nearly  an  inch  above  it  anteriorly;  the  septum  lucidum  is  generally  so 
soft  that  in  this  stage  of  the  dissection  it  will  have  nearly  broke  down  into  the 
surrounding  fluid. 

The  lateral  ventricles  extend  from  the  middle  of  the  brain  into  the  an- 
terior and  posterior  lobes,  also  to  the  inferior  part  of  the  middle  lobes, 
hence  they  are  named  tricorne ; the  anterior  cornu  of  each  passes  forwards 
and  outwards,  and  are  about  an  inch  distant  from  each  other ; the  middle 
portion,  or  the  body  of  each  passes  horizontally  backwards,  and  are  sepa- 
rated from  each  other  by  the  septum  lucidum;  near  the  posterior  part  of 
the  corpus  callosum  the  posterior  and  inferior  cornua  pass  off  in  different 
directions  ; the  posterior  cornu  proceeds  into  the  posterior  lobe  at  first 
outwards,  afterwards  it  turns  inwards  in  a curved  direction,  the  con- 
cavity towards  the  median  line  ; the  inferior  cornu  descends  obliquely  for- 
wards and  outwards,  and  is  then  also  curved  a little  inwards;  it  terminates 
behind  the  fissure  of  Sylvius  and  beneatli  the  anterior  cornu.  The  anterior 
cornu  is  bounded  superiorly  and  laterally  by  the  corpus  callosum,  and  inte- 
riorly by  the  large  extremity  of  the  corpus  striatum;  the  middle,  or  body  of  each, 
is  bounded  superiorly  and  externally  by  the  corpus  callosum  ; internally  by 
the  septum  lucidum,  and  interiorly  by  the  posterior  extremity  of  the  corpus 
striatum,  the  tsenia  semicircularis,  the  optic  thalamus,  the  choroid  plexus,  and 
the  fornix.  The  posterior  cornu  is  bounded  superiorly  and  laterally  by  the 
medullary  substance,  and  interiorly  by  the  hippocampus  minor.  The  inferior 
cornu  is  bounded  superiorly  by  the  optic  thalamus,  externally  by  medullary 
substance  ; internally  it  is  deficient  of  cerebral  substance  and  is  close  by  the 
arachnoid  membrane  ; interiorly  by  the  hippocampus  major  and  corpus  fim- 
briatum  : these  several  bodies,  which  are  observed  in  the  different  regions  of 
these  cavities,  must  next  be  examined  individually  ; and  first,  the  corpora 
striata.  These  pyriform  bodies  have  their  larger  ends  directed  forwards  and 
inwards ; their  posterior  small  and  pointed  extremities  pass  backwards  and 
outwards  ; smooth  and  unattached  superiorly  and  internally,  on  all  other  sides 
they  are  continuous  with  the  white  substance ; vascular,  soft,  and  cineritious 
on  their  surface;  they  will  be  found,  when  cut  into,  to  consist  of  alternate 
laminae  of  gray  and  white  substance ; the  latter  may  be  traced  from  the  crura 
cerebri  through  these  bodies  to  the  upper  and  anterior  part  of  the  cerebrum, 
hence  the  copora  striata  are  named  by  some  the  anterior  or  superior  ganglions 
of  the  cerebrum.  The  taenia  semi-circularis,  a narrow,  semi-transparent  band, 
whitish,  fibrous,  placed  in  the  groove  between  the  optic  thalamus  and  corpus 
striatum  ; arises  narrow  from  a tubercle  on  the  back  part  of  the  optic  thalamus 
(corpus  geniculatum,  externum)  passes  forwards  and  inwards,  becomes 
broader,  and  joins  the  descending  pillar  of  the  fornix ; the  anterior  portion  has  a 
resemblance  to  the  cornea,  and  has  been  named  lamina  cornea ; several  veins 
from  the  corpus  striatum  pass  beneath  the  taenia  to  join  the  venae  Galeni.  The 
choroid  plexus  is  a fold  of  thin  vascular  membrane  derived  from  the  pia  mater  : 
it  enters  the  inferior  cornu  between  the  optic  thalamus  and  the  taenia  hippo- 
campi ; loose  and  floating  it  ascends  obliquely  backwards  over  the  hippocampus 
major,  then  turns  forwards  between  the  thalamus  and  the  fornix,  beneath  which 


OR  MANUAL  OF  ANATOMY. 


169 


it  is  connected  to  the  choroid  membrane,  and  ends  by  uniting  with  its  fellow 
in  the  foramen  commune  anterius ; each  choroid  plexus  is  covered  by  the  arach- 
noid membrane ; they  receive  a number  of  veins  from  the  parietes  of  the 
ventricles,  particularly  from  the  corpora  striata ; these  veins  join  the  vense 
Galeni,  which  will  be  noticed  presently  ; very  frequently  small  vesicles,  hy- 
datids and  even  small  hard  tumors  may  be  found  in  these  membranes. 

The  fornix,  white,  fibrous,  triangular,  is  situated  horizontally,  beneath  the 
corpus  callosum  and  septum  lucidum,  attached  to  the  former  posteriorly,  to 
the  latter  anteriorly,  it  lies  on  the  velum  interpositum  and  choroid  plexuses ; 
the  base  posteriorly,  arises,  by  two  flat  bands,  the  [posterior  pillars  or  crura,) 
one  from  either  side,  from  the  hippocamus,  major  and  minor,  and  from  the 
taenia  hippocampi,  these  crura  pass  forwards  and  inwards,  and  unite  (the  body 
of  the  fornix );  this  bends  forwards  and  downwards,  over  the  foramen 
commune  anterius,  and  divides  into  two  short,  round,  white  cords,  (the 
anterior  pillars  of  the  fornix ) these  descend  behind  the  anterior  commissure, 
and  end  in  the  corpora  mammillaria,  which  are  covered  with  gray  substance 
from  the  tuber  cinerum : the  inferior  surface  of  the  fornix  which  rests  on  the 
velum  is  marked  posteriorly  by  several  fine  oblique  lines  [lyra  or  corpus 
psalloides ).  Although  the  septum  lucidum  is  a partition  between  the  lateral 
ventricles,  yet  these  cavities  communicate  together,  as  also  with  fhe  third  or 
middle  ventricle,  though  an  opening  termed  foramen  commune  anterius , this 
is  situated  in  the  median  line  at  the  anterior  part  of  the  body  of  each  ven- 
tricle, it  is  bounded  superiorly  and  anteriorly  by  the  fornix,  posteriorly  by 
the  two  choroid  plexuses  and  velum,  laterally  it  leads  from  one  lateral  ven- 
tricle to  the  other,  and  interiorly  it  opens  into  the  third.  The  optic  thalami 
cannot  be  fully  examined  at  present.  In  the  posterior  cornu  of  each  ventricle 
is  a small  eminence,  the  hippocampus  minor, -large  anteriorly,  small  and 
pointed  behind,  white  on  the  surface,  gray  internally.  In  the  inferior  cornu 
we  see  the  hippocampus  major,  a large  white  substance,  convex  externally, 
concave  internally,  smooth  and  white  on  the  surface,  gray  within,  extending 
all  along  the  floor  of  the  cavity,  and  ending  in  a tuberculated  expansion,  the 
pes  hippocampi  ; along  its  internal  or  concave  edge,  and  connected  to  it,  is  a 
narrow  white  band,  the  taenia  hippocampi  or  corpus  fimbriatum,  the  concave 
edge  of  which  is  loose ; this  substance  is  directly  continuous  with  the  poste- 
rior pillar  of  the  fornix ; beneath  the  taenia  hippocampi,  a narrow  cineritious 
line  may  be  observed,  shorter  than  the  taenia,  its  edge  is  serrated ; this  is  the 
corpus  denticulatum . Divide  the  fornix  about  its  centre,  draw  forwards  its 
anterior  portion,  and  the  foramen  commune  anterius  will  be  seen  ; throw  the 
posterior  portion  backwards,  and  the  choroid  membrane  or  the  velum  inter- 
positum will  be  exposed  ; this  is  of  a triangular  form,  beneath  the  fornix,  and 
above  the  optic  thalami,  the  pineal  gland,  the  arachnoid  canal,  and  the  third 
ventricle ; the  choroid  plexuses  are  united  to  it  laterally  and  in  front,  the 
venae  galeni  extend  along  its  median  line ; these  veins  receive  the  blood  from 
each  plexus,  and  from  the  different  eminences  in  the  ventricles,  they  pass 
backwards,  and  end  in  the  straight  sinus,  they  sometimes  first  unite  into  one 
trunk  ; the  velum  is  formed  of  pia  mater,  which  is  continued  from  the  surface 
of  the  brain  through  the  great  transverse  fissure,  which  is  beneath  the  corpus 
callosum  and  the  fornix,  and  above  the  tubercula  quadrigemina  and  the  pineal 
gland;  it  is  also  covered  by  the  arachnoid  membrane,  which  is  of  extreme 
22 


170 


THE  DUBLIN  DISSECTOR, 


delicacy;  raise  this  membrane  from  before  backwards,  first  dividing  the  small 
veins  which  run  into  it,  the  optic  thalami  will  be  now  exposed,  and  posterior 
to  these  the  pineal  gland,  and  the  superior  surface  of  the  tubercula  quadri- 
gemina;  the  anterior  extremity  of  the  arachnoid  canal  also  is  seen;  this 
orifice  is  beneath  the  veins  of  Galen  and  above  the  gland,  it  is  in  general  sur- 
rounded by  small  granulations;  remove  the  velum.  The  pineal  gland  is 
situated  above  the  tubercula  quadrigemina,  about  the  size  of  a pea,  cineritious, 
heart-shaped,  the  base  anteriorly  containing,  in  general,  some  small  sandy 
particles  (the  acervulus ) the  posterior  part  is  soft  and  pulpy,  the  ( conarium ) 
is  surrounded  by  a very  vascular  membrane  derived  from  the  velum;  uncon- 
nected to  the  brain  in  every  situation,  except  anteriorly,  whence  a small 
transverse  medullary  band  proceeds,  which  divides  into  two  long  delicate 
processes  ( pedunculi ),  these  pass  forwards  on  the  inner  surface  of  the  optic 
thalami,  and  join  the  descending  pillars  of  the  fornix,  at  the  foramen  commune 
anterius.  The  optic  thalami,  two  firm  bodies  white  on  their  surface,  gray 
within,  placed  behind  and  between  the  corpora  striata,  smooth  superiorly 
where  they  enter  into  the  lateral  ventricles,  touching  each  other  internallv, 
where  they  are  soft  and  grayr ; this  connection  is  termed  the  commissura  mollis, 
it  is  a broad,  soft,  and  cineritious  union  between  the  internal  surfaces  of  the 
thalami,  and  anterior  to  their  centre,  this  must  be  broken  through  before  the 
third  ventricle  can  be  seen  ; a sort  of  fissure  separates  the  thalami  ; this 
fissure  anteriorly  leads  to  the  foramen  commune  anterius,  and  posteriorly  to 
the  foramen  commune  posterius,  this  last  hole  is  behind  the  soft  commissure, 
and  between  the  peduncles  of  the  pineal  gland,  it  is,  however,  so  closed  by  the 
velum  and  the  fornix,  that  no  communication  can  oc  tr  through  it  between 
the  third  and  the  two  lateral  ventricles,  as  through  the  anterior  common  open- 
ing; the  optic  thalami  externally  and  inferiorly  are  continuous  with  the 
corpora  striata  and  the  medullary  substance  of  the  hemispheres ; inferiorlv 
they  present  two  tubercles;  ( corpus  geniculaturn  internum  and  externum  ;) 
their  anterior  extremity  is  in  the  foramen  commune  anterius,  their  posterior 
is  in  contact  with  the  corpus  fimbriatum  ; the  upper  surface  of  each  is  in  the 
body  of  the  lateral  ventricle,  the  inferior  surface  is  in  the  inferior  cornu : 
through  the  substance  of  the  thalami  some  portions  of  the  crura  cerebri  pass 
in  their  course  to  the  convolutions  of  the  hemispheres,  hence  they  are  named 
by  some  the  inferior  ganglions  of  the  brain.  Separate  the  optic  thalami,  and 
the  third  or  middle  ventricle  will  be  opened.  The  third  ventricle  is  a narrow 
cavity  placed  in  the  median  line,  bounded  on  each  side  by  the  optic  thalami, 
above  by  the  velum  and  the  fornix,  below  by  the  locus  perforatus  and  tuber 
cinereuin,  before  by  the  descending  pillars  of  the  fornix  and  the  anterior  com- 
missure, behind  by  the  posterior  commissure  and  pineal  gland,  its  pedunculi 
and  the  tubercula  quadrigemina.  The  foramen  commune  anterius  opens  into 
the  upper  and  anterior  part  of  this  cavity  ; the  infundibulum  leads  from  the 
lower  and  anterior  part  downwards  and  forwards,  bewteen  the  pillars  of  the 
fornix  and  below  the  anterior  commissure,  to  the  pituitary  gland  ; this  canal  is 
large  above,  but  it  is  generally  impervious  below.  From  the  posterior  part 
of  the  third  ventricle  a small  canal  leads  backwards  and  downwards,  above 
and  behind  the  pons  Varolii,  and  belowr  the  tubercula  quadrigemina,  this  is  the 
aqueduct  of  Sylvius,  or  the  iter  ad  quartum  ventriculum - The  anterior 
commissure  is  a distinct  round  cord,  extending  from  one  hemisphere  to  the 


OR  MANUAL  OF  ANATOMY. 


in 


other,  immediately  before  the  anterior  pillars  of  the  fornix,  bent  like  an  arch, 
convex  anteriorly,  unattached  in  its  central  portion,  but  on  each  side  it  is  im- 
bedded in  the  corpus  striatum,  through  which  it  descends  obliquely  back- 
wards and  outwards,  and  then  terminates  in  rays  near  the  fissure  of  Sylvius, 
and  the  inferior  cornu  of  the  lateral  ventricle : it  is  enclosed  in  a delicate 
sheath  of  pia  mater,  like  a nerve.  The  posterior  commissure  is  shorter  and 
smaller  than,  the  anterior,  but  white,  round,  and  fibrous  like  it;  it  extends 
transversely  behind  the  third  ventricle,  above  the  aqueduct  of  Sylvius,  below 
the  pedunculi  of  the  pineal  gland  to  which  it  is  connected,  and  anterior  to  the 
tubercula  quadrigemina;  its  extremities  are  connected  to  the  optic  thalami. 
The  tuberculi  quadrigemina  are  below  this  commissure,  and  the  pineal  gland, 
they  are  all  connected  by  their  bases,  on  an  oblique  plane,  and  separated  from 
each  other  near  their  points  by  two  superficial  grooves;  the  two  superior  and 
anterior  are  called  the  nates,  the  two  inferior  and  posterior  the  testes,  white  on 
their  surface,  gray  internally,  they  lie  above  and  behind  the  aqueduct  of  Sylvius 
which  alone  separates  them  from  the  pons  Varolii;  the  nates  are  connected 
to  the  optic  thalami,  and  the  testes  to  the  cerebellum,  by  two  thin  white  plates, 
which  descend  obliquely  backwards  and  outwards,  and  end  in  the  substance 
of  the  cerebellum  ; these  are  the  processus  a cerebello  ad  testes  ; they  diverge 
towards  the  cerebellum,  and  are  continuous  externally  and  interiorly  with  a 
thick,  round,  white  process,  the  crus  cerebelli;  between  these  two  processes 
there  is  a thin  lamina  extended  named  the  valve  of  Vieussens,  or  of  the  fourth 
ventricle,  cineritious  and  very  soft,  triangular,  the  apex  between  the  testes,  the 
base  attached  to  the  cerebellum,  and  die  sides  to  the  two  processes  just  de- 
scribed ; this  valve  forms  the  roof  of  the  fourth  ventricle.  Pass  a probe  along 
the  aqueduct  of  Sylvius  divide  the  valve  of  Vieussens  and  the  cavity  of  the 
fourth  ventricle  will  be  exposed  ; this  is  directed  obliquely  downwards  and 
backwards,  between  the  cerebrum,  cerebellum,  and  medulla  oblongata ; it  is 
bounded  anteriorly  by  the  pons  Varolii,  in  the  median  line  of  which  is  a 
narrow  fissure,  the  calamus  scriptorius,  from  each  side  of  which  a few  white 
lines  pass  off  to  join  the  auditory  nerve ; laterally  by  the  processes  from  the 
testes  and  by  the  crura  cerebelli;  superiorly  by  the  valve  of  Vieussens; 
posteriorly  by  the  cerebellum,  and  inferiorly  by  the  reflection  of  the  arach- 
noid membrane,  and  of  the  pia  mater  from  the  inferior  surface  of  the  cere- 
bellum to  the  back  of  the  spinal  cord;  the  pia  mater  is  here  peculiarly’’ dense, 
and  it  sends  a small  process  into  the  lower  part  of  this  cavity,  (the  choroid 
plexus  of  the  fourth  ventricle,)  which  is  loaded  with  tortuous  vessels,  and  fre- 
quently presents  a small  number  of  reddish  granular  bodies. 

Raise  either  hemisphere  of  the  cerebrum  ; from  its  inferior  surface,  just  be- 
low the  corpus  striatum  and  the  optic  thalamus,  a thick,  white  fasciculus  may 
be  observed  descending  obliquely  backwards  and  inwards;  this  is  the  crus 
cerebri;  fibrous  and  white  on  the  surface,  each  crus  internally  contains 
cineritious  substance  of  a very  dark  color  ( locus  niger) ; the  crura  cerebri 
converge  as  they  descend,  and  end  in  the  upper  extremity  of  the  pons  Varolii ; 
the  third  ventricle  is  between  them,  and  the  tractus  opticus  of  each  side  sur- 
rounds them.  The  crura  cerebri  and  the  following  substance  can  be  better 
examined  when  the  brain  is  removed  from  the  subject,  and  the  base  placed 
uppermost.  The  pons  Varolii  is  somewhat  square,  it  is  placed  obliquely  on 
the  cuneiform  process,  between  the  cerebrum  and  cerebellum;  the  fourth 


172 


THE  DUBLIN  DISSECTOR, 


ventricle,  the  aqueduct  of  Sylvius  and  the  tubercula  quadrigemina,  are  on  its 
superior  and  posterior  surface ; its  inferior  and  anterior  surface  rests  on  the 
bone,  and  is  grooved  longitudinally  by  the  basilar  artery : its  superior  ex- 
tremity receives  the  crura  cerebri,  which  it  surrounds  like  a ring,  hence  it  is 
sometimes  called  the  annular  protuberance ; the  crura  cerebelli  are  attached 
to  its  sides,  and  the  medulla  oblongata  to  its  lower  extremity,  from  which  it  is 
distinguished  by  a deep  groove  : the  pons  is  of  a more  firm  structure  than  any 
part  of  the  brain,  its  surface  is  white  and  fibrous ; the  superficial  layer  of 
fibres  run  transversely  from  one  crus  cerebelli  to  the  other,  hence  the  pons 
has  been  named  the  commissure  of  the  cerebellum  ; beneath  this  lamina  of 
transverse  fibres  a quantity  of  cineritious  substance  exists,  through  which 
white  fibrous  substance  may  be  seen  to  ascend  obliquely  outwards,  in  the  di- 
rection of  the  crura  cerebri.  The  pons  Varolii  is  described  by  some  authors 
as  a portion  of  the  medulla  oblongata;  it  is,  however,  so  connected  with  it, 
as  well  as  with  the  cerebrum  and  cerebellum,  that  it  may  be  considered  as 
equally  common  to  all. 

DISSECTION  OF  THE  CEREBELLUM. 

Remove  the  posterior  lobes  of  the  cerebrum,  divide  the  tentorium,  and  the 
cerebellum  will  be  exposed;  transversely  oval,  raised  in  the  centre,  divided 
into  right  and  left  hemispheres  by  a deep  groove  posteriorly  and  iuferiorlv, 
which  receives  the  falx  cerebelli,  and  by  a broad  notch  anteriorly,  which  is 
behind  the  fourth  ventricle  ; the  upper  surface  of  each  hemisphere  is  nearly 
flat,  and  is  marked  by  a great  number  of  narrow  lines  which  run  semicircu- 
larly,  convex  posteriorly;  these  are  fissures  into  which  the  pia  mater  descends, 
the  arachnoid  membrane  passing  over  them;  these  fissures  are  analogous  to 
those  in  the  cerebrum ; they  are  involutions  of  the  gray  substance,  the  super- 
ficial extent  of  which  is  thus  considerably  augmented  : the  same  appearance 
is  also  observable  inferiorly ; the  lines,  however,  are  not  so  numerous  or  regular 
as  above  ; some  lines  pass  in  very  deep  into  the  cerebellum,  and  divide  itinto 
lobes,  others  are  only  superficial,  and  divide  itinto  lobules;  the  inferior  sur- 
face of  each  hemisphere  is  very  convex,  and  fills  the  inferior  occipital  fossae. 
Along  the  circumference  of  each  hemisphere  a deep  fissure  extends,  at  the 
bottom  of  which  a white  cord  is  observed;  this  is  the  crus  cerebelli  which  as- 
cends obliquely  forwards  and  inwards  to  join  the  pons  Varolii ; this  great 
fissure  separates  the  superior  from  the  inferior  surface.  The  central  portion 
of  the  cerebellum  is  narrow,  and  raised  superiorly  into  a small  conical  pro- 
cess, the  superior  vermiform  process,  this  overlaps  the  valve  of  Vieussens,  the 
tubercula  quadrigemina,  and  the  processus  a cerebello  ad  testes  ; inferiorly 
there  is  a deep  depression,  which  contains,  anteriorly,  the  commencement  of 
the  spinal  cord,  and  posteriorly  a large  process,  the  inferior  vermiform,  which 
is  marked  by  numerous  transverse  lines  or  fissures,  which  divide  it  into  several 
lamime  or  lobules.  Divide  either  hemisphere  parallel  to,  and  about  an  inch 
from  the  median  line,  a thick  mass  of  white  substance  is  seen  in  the  centre, 
branching  out  into  fine  fibres,  which  extend  into  the  lobes,  and  again  subdivide 
into  fine  filaments,  which  pass  to  every  lamina  or  lobule  on  the  surface,  and 
are  there  covered  by  a thin  layer  of  gray  substance  : nearly  in  the  centre  of 
this  white  mass,  which  is  continuous  superiorly  with  the  processus  adtestem, 


OR  MANUAL  OF  ANATOMY 


173 


and  interiorly  with  the  crus  cerebelli,  is  a small  oval  mass  of  gray  substance, 
its  edges  convoluted  or  serrated : this  is  the  corpus  dentatum  or  rhomboideum  ; 
the  white  substance  which  is  continued  from  the  medulla  oblongata  to  the.  crus 
cerebelli,  appears  to  run  through  this,  and  thus  to  be  increased  in  quantity : 
hence  it  is  named  by  some  the  ganglion  of  the  cerebellum. 

DISSECTION  OF  THE  MEDULLA  OBLONGATA. 

The  medulla  oblongata  is  that  conical  portion  of  white  substance  which  ex- 
tends from  the  lower  margin  of  the  pons  Varolii  to  the  spinal  cord,  about  an 
inch  in  length,  large  above,  narrow  below,  where  it  passes  through  the  foramen 
magnum,  divided  by  longitudinal  lines  into  six  oval  eminences  placed  parallel 
to  each  other;  the  median  line  anteriorly  separates  the  two  corpora  pyrami- 
dalia;  next  to  each  of  these  is  a slight  groove,  external  to  which  is  the  corpus 
olivare,  behind  which  is  a groove  and  another  eminence,  the  corpus  restiforme 
or  the  posterior  pyramid. 

The  corpora  pyramidalia  are  about  an  inch  long,  they  arise  gradually  from 
the  fore-part  of  the  spinal  cord  above  the  atlas,  ascend  parallel  to  each  other, 
increase  in  size,  enter  the  pons,  and  they  may  be  traced  though  this  substance 
for  some  extent;  the  median  fissure,  which  extends  along  the  spinal  cord,  sepa- 
rates them ; near  the  pons  this  fissure  enlarges  into  a small  hole  (foramen 
caecum).  Dissect  off  the  pia  mater  from  these  eminences,  endeavor  to  sepa- 
rate them  from  each  other,  and  about  three  quarters  of  an  inch  below  the  pons 
five  or  six  white  bands  may  be  observed  ascending  obliquely  from  one  corpus 
pyramidale  to  the  other,  the  fasciculi  of  opposite  sides  perfectly  indigitating 
with  each  other;  these  are  the  decussating  fibres  of  the  pyramids. 

The  corpora  olivaria  are  oval,  large  in  the  centre,  white  on  the  surface,  and 
containing  within  a corpus  dentatum  of  gray  substance ; they  are  separated 
by  a superficial  groove  from  the  former  eminences;  their  upper  extremity  is 
continued  into  the  pons  Varolii. 

The  corpora  restifiormia  are  rather  larger  than  the  last  behind  which  they 
are  placed ; they  are  separated  from  each  other  by  a fissure  which  is  continued 
from  the  calamus  scriptorius  along  the  posterior  median  line  of  the  spinal  cord ; 
the  restiform  bodies  are  continued  superiorly  into  the  crura  cerebelli,  hence 
they  are  sometimes  named  the  processus  a medulla  spinali  ad  cerebellum. 

ORIGIN  OF  THE  CEREBRAL  NERVES. 

There  are  nine  pair  of  cerebral  nerves ; their  connection  to  the  brain  is 
named  their  origin  ; they  are  distinguished  by  the  terms  first,  second,  third, 
&c.  &c.  in  every  respect,  those  of  the  opposite  sides  are  symmetrical. 

The  first  pair  or  olfactory  are  situated  beneath  the  anterior  lobes  of  the 
brain  ; each  arises  by  three  filaments,  the  external  very  long  and  white  from 
the  fissure  of  Sylvius,  below  the  corpus  striatum ; the  internal,  also  white,  from 
the  gray  substance  at  the  extremity  of  the  corpus  callosum ; the  middle  is  cin- 
eritious,  and  arises  from  one  of  the  posterior  convolutions  of  the  anterior  lobe  ; 
the  three  filaments  soon  unite  and  form  a triangular  swelling,  from  which  the 
nerve  proceeds  forwards  and  inwards  for  about  two  inches,  in  a groove  in  the 


174 


THE  DUBLIN  DISSECTOR, 


anterior  lobe,  in  which  it  is  protected  from  pressure ; it  then  ends  in  a soft  oval 
bulb  which  is  placed  over  the  cribriform  plate  of  the  ethmoid  bone ; from  this 
several  fine  filaments  descend  through  the  formina  in  this  bone,  and  are  distri- 
buted to  the  mucous  membrane  in  the  nose.  The  olfactory  differ  from  the 
other  cerebral  nerves  in  figure,  course,  and  structure ; prismatic  or  triangu- 
lar, the  apex  is  imbedded  in  the  cerebrum;  they  converge  as  they  leave  the 
cranium  ; they  consist  of  several  striae,  some  white,  others  gray,  all  very  soft; 
they  are  not  surrounded  by  arachnoid  membrane,  but  lie  above  it;  they  have 
no  distinct  sheath,  and  each  ends  in  a soft  gray  swelling  from  which  the  ulti- 
mate filaments  proceed,  and  which  leave  the  cranium  by  a number  of  foramina. 

The  second  pair  or  optic  are  large,  soft,  and  flat  posteriorly ; round  and 
enclosed  in  a dense  neurilema  anteriorly,  each  arises  by  two  bands,  one  from 
the  natis,  the  other  from  the  testis  ; these  pass  outward  beneath  the  optic  tha- 
lamus, the  first  joins  the  corpus  geniculatum  externum,  the  second  the  corpus 
geniculatum  internum  ; these  roots  then  unite  in  a soft  flat  band,  which  turns 
forwards  in  a semicular  course  ( tractus  opticus ) around  the  crus  cerebri,  to 
which  it  has  a slight  attachment,  and  from  which  it  receives  a few  fibres;  the 
optic  nerves  then  converge,  and  unite  before  the  sella  turcica  in  the  optic  com- 
missure; in  this  flat,  white,  square  substance,  which  is  connected  to  and  re- 
ceives additional  fibres  from  the  tuber  cinereum,  the  two  nerves  are  so  con- 
founded that  the  direction  of  each  is  indistinct,  and  it  is  uncertain  whether  they 
decussate  in  whole  or  in  part ; from  the  commissure  each  nerve  passes  forwards 
and  outwards  on  the  inner  side  of  the  carotid  and  above  the  opthalmic  artery, 
though  the  optic  foramen,  into  the  orbit;  it  is  then  surrounded  by  a process 
of  dura  mater,  and  proceeding  to  the  back  part  of  the  eye,  it  perforates  the 
choroid  and  sclerotic  coats  of  this  organ,  and  terminates  in  the  retina. 

The  third,  or  motores  oculorum,  are  smaller  than  the  optic;  each  arises 
from  the  inner  side  of  the  crus  cerebri,  close  to  the  pons,  behind  the  floor  of 
the  third  ventrical,  and  between  the  posterior  artery  of  the  cerebrum  and  the 
anterior  artery  ot  the  cerebellum  ; this  round  nerve  passes  forwards  and  out- 
wards external  to  the  cavernous  sinus,  through  the  foramen  lacerum  orbitale 
and  is  distributed  to  five  of  the  seven  muscles  contained  in  the  orbit. 

The  fourth  or  trochleatores  are  the  smallest  of  the  cerebral  nerves ; 
each  arises  by  two  or  three  delicate  filaments  from  the  valve  of  Vieussens  and 
from  the  processus  a cerebello  ad  testem  ; it  takes  a long  course  forwards  and 
outwards  between  the  cerebrum  and  cerebellum,  enters  a small  canal  between 
the  layers  of  the  tentorium,  behind  the  posterior  clinoid  process,  and  continues 
its  course  along  the  outer  side  of  the  cavernous  sinus  through  the  foramen 
lacerum  orbitale  to  the  superior  oblique  muscle. 

The  fifth  or  trifacial  or  trigemni  are  the  largest  of  the  cerebral  nerves; 
each  consists  of  nearly  one  hundred  fine  filaments,  but  loosely  connected  to  each 
other,  and  very  easily  detached  from  the  brain  ; arises  by  two  fasciculi,  one 
from  the  angle  between  the  pons  Varolii  and  the  crus  cerebelli,  the  other  from 
the  corpus  pyramidale  in  the  substance  of  the  pons;  these  pass  together  for- 
wards and  outwards  over  the  point  of  the  petrous  bone  in  a sort  of  canal 
formed  of  dura  mater,  and  lined  by  arachnoid  membrane,  which  last  is  reflected 
on  the  nerve,  so  as  to  form  a cul  de  sac  around  it;  in  the  middle  fossa  of  the 
base  of  the  cranium  it  expands  into  a large  gray  swelling  (the  triangular. 


OR  MANUAL  OF  ANATOMY. 


175 


semilunar,  or  gasserian  ganglion  ;)  this  ganglion  is  concave  posteriorly convex 
anteriorly  and  externally ; the  dura  mater  covers  and  adheres  intimately  to 
its  plexiform  surface;  three  large  branches  proceed  from  it,  the  opthalmic, 
the  superior  and  inferior  maxillary  ; the  first  passes  into  the  orbit  through  the 
foramen  lacerum;  the  second  leaves  the  cranium  by  the  foramen  rotundum, 
and  the  third  by  the  foramen  ovale.  If  the  ganglion  be  raised  from  the  bone, 
a small  fasciculus  of  fibres  may  be  observed  to  pas's  from  the  trunk  of  the  fifth 
pair,  without  entering  into  the  ganglion,  to  the  inferior  maxillary  nerve;  this 
fasciculus  can  be  traced  into  the  anterior  root  of  the  fifth,  or  into  the  pons 
Varolii.  When  this  nerve  is  detached  from  the  brain,  a small  nipple-like 
tubercle  is  seen  on  the  latter  at  the  point  of  separation.  The  fifth  pair  of 
nerves  resemble  spinal  nerves,  in  arising  by  two  roots,  and  in  having  a gan- 
glion placed  on  the  posterior,  to  which  the  anterior  is  only  connected. 

The  sixth  or  abducentks,  are  of  a middle  size  between  the  third  and  fourth ; 
each  arises  from  the  outer  side  of  the  corpus  pyrainidale,  a little  below  the 
pons,  it  passes  forwards  and  outwards,  pierces  the  dura  mater  behind  the  body 
of  the  sphenoid  bone,  traverses  the  cavernus  sinus  on  the  outer  side  of  the 
carotid  artery,  and  is  there  joined  by  two  or  three  small  filaments  from  the 
superior  cervical  gangloin  of  the  sympathetic  nerve,  it  then  enters  the  orbit 
through  the  foramen  lacerum,  and  is  distributed  to  the  external  rectus  muscle; 
the  basilar  artery  is  between  the  sixth  pair  of  nerves. 

The  seventh  pair  consists  of  two  portions,  the  portio  dura  or  the  facial 
nerve  and  the  portio  mollis  or  the  auditory  nerve;  the  facial  nerve  arises 
from  the  lower  edge  of  the  side  of  the  pons  below  the  crus  cerebelli,  and  rather 
behind  and  above  the  corpus  olivare  ; the  auditory  nerve  or  portio  mollis  arises 
by  three  or  four  striae  from  the  side  of  the  calamus  scriptorius  and  from  a 
small  mass  of  gray  substance  on  the  back  of  the  corpus  restiforme.;  these  are 
at  first  separated  by  the  restiforme,  but  soon  unite  into  one  soft  white  cord, 
which  passes  forwards  and  outwards  and  joins  the  portio  dura ; the  two  nerves 
theu  pass  outwards,  the  mollis  being  larger  than  the  dura,  which  is  contained 
in  a groove  in  the  former,  and  a small  blood  vessel  runs  between  them  ; they 
both  enter  the  meatus  auditorius  internus,  where  they  soon  separate  ; the  fa- 
cial nerve  runs  along  the  aqueduct  of  Fallopius,  which  canal  opens  inferiorly 
at  the  stylo-mastoid  foramen  ; this  nerve  then  turns  forwards,  and  is  distri- 
buted to  the  side  of  the  face  ; the  auditory  nerve  descends  obliquely  forwards, 
and  is  distributed  to  the  cochlea  and  semicircular  canals. 

The  eighth  pair,  or  the  par  vaguji,  consists  of  three  portions,  the  glosso- 
pharyngeal, the  pneumo-gastric,  and  the  spinal  accessory;  the  glosso- 
pharyngeal arises  by  four  or  five  delicate  filaments  between  the  corpus  olivare 
and  restiform ; these  unite  into  one  small  nerve ; the  pheumo-gastric  or  the 
vagus,  arises  by  ten  or  twelve  filaments  below  the  last,  but  in  the  same  groove ; 
these  also  unite  into  one  nerve,  which,  with  the  glosso-pharyngeal,  passes  for- 
wards and  outwards  to  the  foramen  lacerum  posterius  or  jugular,  where  they 
are  joined  by  the  spinal  accessory,  which  arises  about  the  middle  of  the  neck 
from  the  side  of  the  medulla  spinalis  by  several  small  roots ; this  nerve  ascends 
behind  the  ligamentum  denticulatum,  and  very  near  the  posterior  roots  of  the 
spinal  nerves;  it  frequently  receives  filaments  from  the  roots  of  these  nerves: 
having  passed  through  the  foramen  magnum  it  joins  the  other  divisions  of  the 
eighth  pair,  the  inferior  artery  of  the  cerebellum  having  previously  passed 


176 


THE  DUBLIN  DISSECTOR, 


between  them.  The  eighth  pair  of  nerves  passes  through  the  jugular  foramen 
anterior  to  the  vein  and  immediately  separates  into  its  three  portions,  the 
course  of  which  shall  be  considered  afterwards  The  spinal  accessor}^  is  dis- 
tributed to  the  muscles  on  the  side  of  the  neck  ; the  glosso-pharyngeal  to  the 
pharynx  and  the  tongue,  and  the  pneumo-gastric  to  the  lungs  and  stomach. 

The  ninth  or  lingual  nerve  arises  by  six  or  eight  line  filaments  between 
the  corpus  olivare  and  pyramidale,  and  behind  the  vertebral  artery;  these 
unite  and  pass  through  the  lingual  or  anterior  condyloid  hole  in  the  occipital 
bone.  The  ninth  pair  of  nerves  are  distributed  to  the  muscles  of  the  tongue. 

Before  the  student  dissects  the  cerebral  nerves  to  their  termination,  he  may 
examine  the  spinal  marrow,  also  dissect  the  brain  from  below  upwards. 


CHAPTER  II. 

DISSECTION  OF  THE  MEDULLA  SPINALIS. 

The  spinal  marrow  is  contained  in  a cavity  or  canal  which  is  bounded  bv 
the  bodies  and  processes  of  the  vertebrae  and  by  their  connecting  ligaments; 
this  organ,  like  the  brain,  is  surrounded  by  three  membranes,  which  are  con- 
tinuous with  those  in  the  cranium.  Place  the  subject  on  the  fore-part,  remove 
the  soft  parts  covering  the  spine,  and  with  the  saw  divide  the  crura  of  the 
spinous  processes  of  all  the  vertebrae  close  to  the  articulating  processes,  then 
with  the  elevator  raise  the  posterior  arch  of  the  spinal  canal ; a quantitv  of 
loose  reddish  cellular  tissue  intervenes  between  the  bones  and  the  dura  mater, 
which  membrane  is  loosely  connected  to  them,  and  does  not  serve  the  office 
of  periosteum  as  in  the  cranium  ; it  is  more  closely  attached  to  the  ligaments 
and  bones  anteriorly  than  laterally  or  posteriorly. 

The  dura  mater  of  the  spinal  canal  is  termed  the  theca  vertebralis ; it  is 
continued  from  the  cranium  through  the  foramen  magnum,  down  the  spinal 
canal  as  far  as  the  third  lumbar  vertebra,  where  it  divides  into  several  pro- 
cesses, which  are  continued  on  the  sacral  nerves;  throughout  this  extent  it 
regulai'ly  sends  off  a tubular  process  along  each  of  the  spinal  nerves;  its  ex- 
ternal surface  is  smooth  and  polished.  With  the  scissors  divide  this  membrane 
along  its  whole  length;  its  internal  surface  will  be  found  lined  by  the  reflected 
layer  of  the  arachnoid  or  serous  membrane. 

The  arachnoid  or  the  serous  membrane  in  this  region  has  a corresponding 
appearance  to  that  in  the  cranium  ; it  is,  however,  rather  stronger,  and  more 
loosely  connected  to  the  pia  mater,  so  that  air  or  any  fine  fluid  may  be  im- 
pelled between,  them ; from  the  sides  of  the  spinal  marrow  it  is  regularly 
reflected  along  each  of  the  nerves  to  the  dura  mater;  these  several  reflections 
or  folds,  when  examined  in  succession,  are  found  to  be  continuous  with  each 
other,  and  i ssist  in  forming  the  following  substance,  the  ligamentum  denticu- 
latum;  this  is  a narrow  membranous  and  ligamentous  band  extending  along 
each  side  of  the  whole  spinal  cord^its  superior  extremity  is  attached  to  the 
dura  mater  at  the  foramen  magnum  ; its  internal  edge  is  straight  and  is  con- 
nected to  the  pia  mater  along  the  side  of  the  spinal  cord  in  the  space  between 
the  anterior  and  posterior  roots  of  the  spinal  nerves;  its  external  edge  is 


OR  MANUAL  OF  ANATOMY. 


177 


serrated  and  attached  by  several  pointed  processes  to  the  inner  surface  of  the 
dura  mater,  near  the  foramina  for  the  passage  of  the  nerves;  each  of  these 
processes  lies  between  the  anterior  and  posterior  fasciculi  of  the  nerves;  its 
inferior  extremity  is  inserted  into  the  ligamentous  substance  on  the  body  of' 
the  fourth  or  fifth  lumbar  vertebra.  The  ligamentum  denticulatum  serves  to 
separate  the  roots  of  the  spinal  nerves,  also  to  connect  or  fix  the  spinal  cord 
laterally. 

The  jria  mater  in  the  spinal  canal  is  more  dense  than  in  the  cranium,  it 
adheres  so  closely  to  the  spinal  cord  as  to  appear  to  compress  it,  which  is  evi- 
dent when  the  cord  is  cut  across ; it  is  not  so  uniformly  vascular  as  it  is  on 
the  brain,  very"  large  and  tortuous  vessels,  howe'ver,  extend  along  its  whole 
length. 

The  medulla  spinalis  extends  from  the  foramen  magnum,  where  it  is  con- 
tinuous with  the  medulla  oblongata  as  far  as  the  second  lumbar  vertebra, 
where  it  ends  in  a lash  of  nerves  called  cauda  equina  ; this  organ  is  almost 
cylindrical;  its  transverse  diameter  exceeds  the  antero-posterior ; a deep 
narrow  fissure  extends  along  the  median  line  posteriorly,  and  a broad  super- 
ficial groove  anteriorly ; at  first  the  medulla  spinalis  is  rather  contracted  or 
smaller  than  the  medulla  oblongata ; but  from  the  fifth  cervical  to  the  first 
dorsal  vertebra  it  is  smaller  than  in  any  other  situation ; it  then  again  swells 
out  into  an  oval  bulbous  expansion  which  terminates  at  the  second  lumbar 
vertebra  in  a point,  from  which  the  remains  of  the  ligamenta  dentata  extend  ; 
this  lower  extremity  of  the  spinal  cord  is  sometimes  round,  sometimes  bifid  : 
the  two  enlargements  of  the  spinal  cord  correspond  to  the  origins  of  the  largest 
nerves,  viz.  those  to  supply  the  upper  and  the  lower  extremity.  The  medulla 
spinalis  appears  to  consist  of  the  two  symmetrical  portions  united  at  the  bot- 
tom of  the  two  fissures  by  transverse  bands  or  commissures^;  if  either  side  be 
divided  by  a transverse  section,  it  will  be  found  to  consist  of  gray  and  white' 
substance,  the  latter  placed  externally,  the  former  internally,  and  of  a lunated 
appearance,  the  concavity  looking  outwards ; some  gray  substance  is  also 
placed  transversely,  and  connects  the  convexities  of  these  lateral  masses. 
The  younger  the  subject  the  more  distinct  is  the  cineritius  substance  in  the 
spinal  cord.  The  medullary  substance  on  each  side  appears  to  be  arranged 
in  three  columns,  separated  by  superficial  grooves ; from  these  the  spinal 
nerves  proceed,  and  it  has  been  partly  ascertained  by  Majendie  and  Bell  that 
the  posterior  roots  of  these  nerves  are  endowed  with  sensation  only,  that  the 
anterior  are  connected  with  voluntary  motion,  and  the  middle,  or  those  which 
arise  from  the  sides  of  the  cord,  with  respiration. 

In  addition  to  the  spinal  accessory  nerves,  which  may  be  now  seen  to  arise 
from  each  side  of  the  medulla  spinalis  in  the  upper  half  of  the  neck  by  twelve 
or  fourteen  small  filaments,  and  to  ascend  behind  the  ligamenta  denticulata, 
the  spinal  cord  gives  origin  to  thirty  pair  of  nerves. 

ORIGIN  OF  THE  SPINAL  NERVES. 

The  spinal  nerves  are  symmetrical  ; there  are  thirty  pair,  which  are  divided 
into  eight  cervical,  twelve  dorsal,  five  lumbar,  and  five  sacral ; all  these  nerves 
arise  and  terminate  nearly  in  a similar  manner ; each  spinal  nerve  is  at 
first  composed  of  two  roots,  an  anterior  and  posterior,  each  of  which  consists 
23 


178 


THE  DUBLIN  DISSECTOR, 


of  several  filaments,  which  arise  from  the  anterior  and  posterior  surface  of  the 
spinal  cord  on  either  side  of  the  median  fissures ; these  filaments  unite  into 
fasciculi ; those  composing  the  posterior  root  are  larger  than  those  in  the  an- 
terior; these  two  fasciculi  or  roots  are  separated  from  each  other  by  the  side 
of  the  spinal  cord,  and  by  the  ligamentum  dentatum  ; they  then  converge  and 
proceed  obliquely  outwards  and  downwards  to  the  dura  mater,  which  they 
perforate  distinctly  by  two  small  openings,  which,  however,  are  so  close,  as  to 
appear  but  one;  each  fasciculus  receives  a sheath  from  the  dura  mater,  they 
then  pass  through  the  inter-vertebral  foramen,  and  in  this  situation  a small 
oval  ganglion  is  formed  upon  the  posterior  root  of  each,  to  the  surface  of  this 
ganglion  the  anterior  root  is  only  connected ; immediately  on  the  outer  side 
of  this  ganglion  the  two  roots  unite  and  form  a single  cord  ; this  is  the  proper 
spinal  nerve ; after  a short  course  outwards,  this  divides  into  two  branches,  a 
posterior  and  an  anterior;  the  former  is  almost  universally  the  smaller,  and 
is  distributed  to  the  muscles  and  integuments  posterior  to  the  vertebral  column; 
the  anterior  branches  of  the  spinal  nerves  are  much  larger ; they  enter  into 
several  plexuses,  and  supply  the  muscles  anterior  to  the  spinal  column,  as  also 
the  extremities.  The  superior  cervical  nerves  take  nearly  a transverse  course 
from  their  origin  to  the  inter-vertebral  foramina ; the  succeeding  nerves  are 
more  oblique,  and  the  lumbar  and  sacral  take  a longitudinal  course,  and  form 
their  ganglions  and  subsequent  divisions  within  the  spinal  canal.  The  course 
and  distribution  of  the  spinal  nerves  shall  be  examined  individually  afterwards, 
the  student  may  next  dissect  the  brain  from  below. 

DISSECTION  OF  THE  BRAIN  FROM  BELOW. 

The  brain,  medulla  oblongata,  and  the  upper  part  of  the  spinal  cord  should 
be  carefully  removed  from  the  subject;  the  brain,  with  the  base  uppermost, 
should  then  be  placed  in  a shallow  basin ; the  cerebellum  and  medulla  oblongata 
will  now  fall  a little  backwards,  and  all  the  parts  of  the  base  of  the  brain  will 
be  exposed.  Raise  the  pie  mater  from  the  fore-part  and  sides  of  the  medulla 
oblongata ; the  several  eminences  on  this  organ  may  be  traced  upwards  to  the 
cerebrum,  or  to  the  cerebellum  ; to  follow  these  the  dissector  should  rather 
scrape  the  surrounding  substance  with  the  handle  or  with  the  back  of  the  knife, 
then  cut  it  with  the  edge.  In  the  description  of  the  brain  already  given,  certain 
differences  between  the  cineritious  and  the  white  substances  have  been  stated  ; 
it  is  necessary  to  recollect  that  the  former  is  soft,  vascular,  and  pulpy,  and 
that  the  latter  is  fibrous ; it  is  an  opinion  entertaind  by  many,  particularly  Gall 
and  Spurzheim,  that  the  gray  is  the  origin  or  matrix  of  the  white  substance,  or 
that  the  former  is  a secreting-  organ,  and  that  the  latter  consists  of  fine  con- 
ducting  vessels  or  filaments;  the  direction  of  the  fibres  in  some  situations  is 
very  distinct;  some  pass  from  below  upwards  and  outwards  ; these  are  termed 
the  diverging  fibres,  others  pass  from  the  surface  or  circumference  down- 
wards and  inwards,  these  are  the  converging  or  uniting  fibres  : first  proceed 
to  trace  these  two  orders  of  fibres  in  the  cerebellum. 

STRUCTURE  OF  THE  CEREBELLUM.. 

Trace  the  restiform  body  upwards  into  the  crus  cerebelli ; divide  this  sub- 
stance vertically,  and  the  former  may  be  seen  continued  into  the  mass  of  gray 


OR  MANUAL  OF  ANATOMY. 


179 


substance  in  the  crus  known  by  the  name  of  corpus  dentatum,  or  the  ganglion 
of  the  cerebellum ; from  the  inner  edge  of  this  a narrow  white  fasciculus  may 
be  traced  inwards  towards  the  median  line ; it  there  unites  with  a similar  pro- 
cess from  the  opposite  side,  and  both  divide  into  several  fine  bands,  which 
diverge  and  form  the  vermiform  process,  (or  the  primary  portion  of  the  cere- 
bellum;) the  peripheral  extremities  of  these  fibres  are  covered  by  cineritious 
substance,  and  present,  when  cut  vertically,  an  arborescent  appearance  ; the 
remainder,  or  the  principal  portion  of  the  restiform  body,  passes  upwards  and 
outwards  through  the  corpus  dentatum  and  then  divides  into  several  processes 
or  stalks  which  diverge  through  each  hemisphere  and  subdivide  into  finer 
branches,  each  of  which  is  covered  by  the  gray  substance  on  the  surface;  a 
vertical  section  of  either  hemisphere  presents  also  that  arborescent  appearance 
known  by  the  name  of  arbor  vitae.  The  converging  fibres  of  the  cerebellum 
are  inferior  and  superior ; the  latter  are  very  delicate  and  rather  indistinct  in 
their  course ; they  consist  of  several  fibres  whichissue  from  the  vermiform  pro- 
cess and  unite  in  one  broad  lamina  which  is  thin  in  the  centre,  (the  valve  of 
Vieussens,)  and  thick  at  each  side  (processus  a cerebello  ad  testes) ; thus  the 
superior  converging  fibres  connect  the  cerebellum  to  the  quadrigeminal  bodies. 
The  inferior  converging  fibres  are  more  distinct,  they  proceed  from  the  cineri- 
tious substance  in  either  hemisphere,  forwards  and  inwards,  and  form  the  prin- 
cipal portion  of  each  crus  cerebelli ; they  then  pass  transversely  across  the  pons 
Varolii  and  unite  with  those  from  the  opposite  side;  thus  the  superficial  lamina 
of  the  transverse  fibres  of  the  pons  form  acommissure  between  the  hemispheres 
of  the  cerebellum. 

STRUCTURE  OF  THE  CEREBRUM. 

Remove  the  pia  mater  from  the  anterior  pyramids  of  the  medulla  oblongata 
and  separate  these  from  each  other,  the  decussating  fibres  will  be  seen,  through 
these  the  pyramid  on  one  side  may  be  said  to  arise  from  the  spinal  cord  of  the 
opposite  side : as  the  pyramids  approach  the  pons  they  are  somewhat  con- 
tracted ; on  entering  this  substance  they  separate  into  fasciculi,  which  intermix 
with  cineritious  substance;  they  are  considerably  increased  in  size  and  number 
in  passing  through  the  pons,  and  they  then  form  the  anterior  and  external  two- 
thirds  of  the  crura  cerebri.  The  olivary  body  and  a few  fibres  from  the  restiform 
of  each  side  also  ascend  through  the  pons  behind  the  fasciculi  of  the  pyramids ; 
these  also  increase  in  size  in  passing  through  the  pons  and  then  enter  the  crura 
cerebri,  the  posterior  and  internal  part  of  which  they  form.  Each  crus  cerebri 
contains  a mass  of  cineritious  substance  of  a peculiarly  dark  color,  in  passing 
through  which  the  white  fibres  appear  increased  in  quantity.  The  posterior  and 
internal  fasciculi  of  each  crus  ascend  and  pass  into  those  masses  of  gray  sub- 
stance called  the  optic  thalami  corpora  striata,  in  passing  through  these  their 
fibres  are  increased  in  number,  and  thence  extend  in  a radiated  manner  into  the 
posterior  and  superior  convolutions  of  each  hemisphere,  where  they  are  covered 
by  a layer  of  gray  substance.  The  anterior  and  external  portion  of  each  crus, 
which  is  in  continuaton  with  corpus  pyramidale,  in  like  manner  ascends  and 
expands  into  fasciculi,  which  may  be  traced  into  the  inferior,  and  external  con- 
volutions of  each  hemisphere.  The  uneven  surface  known  by  the  name  of 


180 


THE  DUBLIN  DISSECTOR, 


convolutions  appears  to  depend  on  the  unequal  length  of  these  diverging  fibres ; 
if  they  were  all  of  equal  extent  the  surface  of  the  cerebrum  would  be  smooth,  but 
as  some  fall  short  of  others,  and  all  are  covered  by  the  gray  substance,  an  uneven 
or  convoluted  surface  is  the  result.  From  this  gray  substance  which  covers 
the  surface  of  each  convolution,  the  converging  or  descending  fibres  are  de- 
scribed as  arising,  and  thence  passing  towards  the  mesial  line  to  unite  with 
those  from  the  opposte  side ; the  corpus  callosum  and  the  anterior  and  posterior 
commissures  are  supposed  to  be  thus  formed;  in  addition  to  these  transverse  pro- 
cesses there  are  several  other  parts  which  may  serve  as  media  of  communication 
between  different  parts  in  each  hemisphere  of  the  brain,  viz.  the  fornix,  the 
taenia  semicircularis,the  pineal  gland,  and  its  pedunculi,  the  infundibulum,  the 
septum  lucidum,  &c.  &c. 

tESSELS  OF  THE  BRAIN. 

The  brain  is  supplied  with  blood  by  the  two  vertebral  and  the  two  internal 
carotid  arteries.  The  vertebral  arteries  are  the  first  branches  of  the  subclavian 
arteries,  each  ascends  through  the  series  of  foramina  in  the  transverse  processes 
of  the  cervical  vertebrae,  and  passing  through  the  foramen  magnum  into  the 
cranium,  they  proceed  obliquely  forwards  and  inwards  and  end  in  a common 
trunk  called  the  basilar  artery ; each  vertebral  first  send  oft'  two  long  and  deli- 
cate branches,  one  on  the  anterior,  the  other  on  the  posterior  surface  of  the  spinal 
cord,  these exteqd  the  whole  length  of  diis  organ,  supplying  it  with  blood,  and 
sending  out  small  branches  along  the  several  spinal  nerves;  next  to  these 
branches  each  vertebral  gives  off  the  inferior  artery  of  the  cerebellum  ; this 
turns  backwards  between  the  pneumo-gastric  and  spinal  accessory  nerves,  and 
is  distributed  to  the  inferior  surface  of  the  cerebellum. 

The  basilar  .artery  ascends  along  the  median  groove  in  the  pons,  and  at  its 
superior  edge  divides  into  four  branches,  two  for  each  side,  viz.  the  superior 
cerebellar  artery  and  the  posterior  cerebral ; these  are  distributed  as  their 
names  imply:  the  posterior  cerebral  artery  of  each  side  is  joined  by  the  pos- 
terior branch  of  each  internal  carotid;  this  communication  completes  the  cir- 
cle of  Willis.  Each  internal  carotid  artery  winds  obliquely  forwards,  up- 
wards, and  inwards,  through  the  tortuous  canal  in  the  temporal  bone,  and 
through  the  cavernous  sinus  ; beneath  the  anterior  clinoid  process  it  perforates 
the  dura  mater,  and  rises  perpendicularly  to  the  base  of  the  brain  between  the 
second  and  third  nerves,  and  then  divides  into  three  branches,  the  anterior, 
middle,  and  posterior ; before  it  thus  divides  it  gives  off,  first,  small  branches 
to  the  cavernous  sinus  and  to  the  dura  mater,  and  next  the  ophthalmic  artery 
which  enters  the  orbit  through  the  optic  hole  and  is  distributed  to  the  eye  and 
its  appendages.  The  anterior  branch  of  the  carotid  is  also  named  the  an- 
terior cerebral  artery,  or  the  artery  of  the  corpus  callosum  ; this  passes  for- 
wards and  inw'ards,  and  is  joined  to  the  corresponding  artery  of  the  opposite 
side  by  a short  branch,  (the  anterior  communicating  artery,)  it  then  ascends 
and  runs  along  the  upper  surface  of  the  corpus  callosum,  distributing  its 
branches  to  the  inner  surface  of  each  hemisphere  ; the  middle  branch  of  the  caro- 
tid is  very  large,  it  passes  upwards  and  outwards  deep  in  the  fissure  of  Sylvias, 
and  is  distributed  to  the  anterior  and  middle  lobes  of  the  cerebrum  ; the  pos- 
terior branch  of  the  carotid  is  named  the  posterior  communicating  artery;  it 


OR  MANUAL  OF  ANATOMY. 


181 


is  small,  passes  backwards,  and  joins  the  posterior  cerebral  artery ; this  forms 
the  side  of  the  circle  of  Willis.  (See  AnatUmy  of  Vascular  System.) — The 
vessels  of  the  brain  are  accompanied  by  numerous  fine  filaments  of  the  sym- 
pathetic nerve,  these  pass  into  its  substance  and  supply  its  intimate  structure. 
The  veins  of  the  brain  empty  themselves  into  the  sinuses  which  have  been  al- 
ready described;  the  principal  veins  are  on  the  superior  surface  of  the  brain, 
whereas  the  large  arteries  are  below. 


CHAPTER  III. 

DISSECTION  OF  THE  NERVES. 

The  course  and  ultimate  distribution  of  most  of  the  nerves  have  been  al- 
ready mentioned  in  the  description  of  the  muscles  and  of  the  several  regions 
of  the  body;  in  the  present  chapter  they  shall  be  considered  in  a' systematic 
manner,  commencing  with  the  cerebral  nerves,  the  origins  of  which  have  been 
already  described. 

§ 1. — Dissection  of  the  Cerebral  Nerves. 

Olfactory  nerves  : from  the  bulb,  which  each  of  these  nerves  forms  at  the 
side  of  the  crista  galli,  several  branches  descend  into  the  nose,  through  the 
foramen  in  the  cribriform  plate ; they  may  be  divided  into  the  internal,  middle, 
and  external.  The  internal  branches,  about  ten  in  number,  descend  in 
grooves  along  the  septum,  subdivide  into  many  filaments  which  form  a plexus 
with  each  other  in  the  mucous  membrane;  some  of  these  can  be  traced  near- 
ly to  the  floor  of  the  nose.  The  middle  branches  are  distributed  to  the  mu- 
cous membrane  lining  the  roof  of  each  nostril.  The  external  branches  descend 
along  the  grooves  on  the  turbinated  bones,  dividing  and  communicating  fre- 
quently with  each  other,  so  as  to  form  numerous  plexuses,  which  are  lost  in 
the  pituitary  membrane.  All  the  branches  of  the  olfactory  nerves  are  very 
soft  in  the  cranium,  but  in  passing  through  the  ethmoid  bone  they  each  receive 
a sheath  from  the  dura  mater,  which  is  ultimately  lost  in  the  external  layer 
of  the  mucous  membrane. — (See  the  Anatomy  of  the  Nose.) 

Optic  Nerves:  each  optic  nerve,  on  passing  through  the  optic  foramen, 
becomes  surrounded  by  a strong  sheath  derived  from  the  dura  mater;  the 
four  recti  muscles  next  surround  it,  from  the  fleshy  portions  of  which  it  is 
separated  by  a considerable  quantity  of  soft  fat,  in  which  several  nerves  and 
vessels  are  lodged  ; from  the  optic  foramen  this  nerve  proceeds  forwards  and 
a little  inwards,  so>as  to  be  slightly  curved,  the  convexity  outwards;  at. the 
back  part  of  the  eye  it  is  very  much  constricted;  it  then  pierces  the  sclerotic 
and  choroid  membranes  and  terminates  in  the  retina.  (See  Anatomy  of  the 
Eye.)  The. ophthalmic  artery  accompanies  this  nerve,  in  the  optic  foramen  it 
lies  beneath  it,  it  afterwards  twines  around  it  to  its  internal  side.  In  addi- 
tion to  the  dura  mater,  this  nerve  possesses  a very  dense  neurilema  which 
sends  in  numerous  processes  to  form  small  canals  or  tubes  in  which  the 
nervous  substance  is  contained,  so  that  this  nerve  is  not  composed  like  other 


182 


THE  DUBLIN  DISSECTOR, 


nerves,  of  several  filaments  placed  parallel  to  each  other;  if  the  white  sub- 
stance be  removed  by  maceration  in  alkali,  its  cellular  structure  will  become 
obvious. 

At  the  side  of  the  body  of  the  sphenoid  bone,  the  following  four  nerves  of 
the  orbit  lie  according  to  their  numerical  order,  viz.  most  superiorly  the  third 
pair,  then  the  fourth,  next  the  ophthalmic  branch  of  the  fifth  pair,  and  most 
interiorly  the  sixth  or  abducens  nerve ; they  are  here  closely  united  to  each 
other,  forming  what  may  be  termed  the  orbital  plexus,  until  they  arrive  at  the 
anterior  clinoid  process,  where  they  separate,  and  as  they  are  entering  the 
foramen  lacerum  orbita'le  they  lie  thus  ;■  most  superior  is  the  fourth,  then  the 
frontal  branch  of  ophthalmic,  next  the  superior  division  of  the  third,  external 
to  which,  and  near  to  the  outer  wall  of  the  orbit,  is  lachrymal  nerve  of  the 
ophthalmic,  after  these  the  nasal  nerve,  below  which  is  the  inferior  division  of 
the  third,  and  lastly  lying  inferior  to  them  all,  holding  the  same  relation  to 
them  as  at  the  cavernous  sinus,  is  the  sixth  nerve. 

To  expose  these  four  nerves  the  orbit  should  be  opened,  which  is  to  be  done 
by  dividing  the  orbital  plate  of  the  os  frontis  by  two  cuts  with  the  saw,  these 
should  unite  in  the  optic  foramen;  the  internal  is  to  be  carried  forward  to  the 
superciliary  arch  about  half  an  inch  external  to  the  internal  angular  process; 
the  external  incision  is  to  be  carried  deeply  through  the  malar  bone  ; a slight 
blow  with  the  hammer  will  then  throw  forwards  the  roof  of  the  orbit,  and  the 
bone  will  separate  easily  from  the  periosteum. 

The  third  pair,  or  motores  oculorum,  in  passing  through  the  foramen 
lacerum  orbitale,  divide  into  two  branches,  a superior  and  inferior:  the  supe- 
rior, or  the  smaller,  passes  between  the  heads  of  the  external  rectus  muscle 
and  over  the  optic  and  nasal  nerves,  and  divides  into  two  branches,  the 
smaller  and  shorter  one  of  which  supplies  the  superior  rectus,  the  other  the 
levator  palpebrae  muscle.  The  inferior  or  the  larger  branch  passes  below  and 
to  the  outside  of  the  optic  nerve  and  divides  into  three  branches,  an  internal, 
middle,  and  external ; the  internal  is  the  largest,  it  passes  obliquely  down- 
wards, forwards,  and  inwards,  beneath  the  optic  nerve,  and  getting  to  its 
internal  side  is  distributed  to  the  internal  rectus,  the  middle  to  the  inferior 
rectus ; and  the  external,  which  is  the  longest,  passes  downwards  and  for- 
wards on  the  surface  of  the  inferior  rectus,  between  it  and  the  globe  of  th« 
eye,  (it  gives  no  filaments  to  this  muscle,)  and  is  lost  in  the  inferior  oblique 
muscle ; this  last  branch  gives  off  from  its  root  a small  short  filament  to  the 
ophthalmic  ganglion.  All  the  branches  of  the  third  pair  are  distributed  to  the 
ocular  surface  of  the  muscles. 

The  trochleator,  or  fourth  nerve,  having  entered  the  orbit  by  the  foramen 
lacerum,  ascends  obliquely. forwards  and  inwards  above  the  levator  palpebrae 
and  *the  superior  rectus,  and  is  distributed  by  four  or  five  fine  branches  to  the 
upper  surface  of  the  superior  oblique  muscle:  as  this  delicate  nerve  is  passing 
along  the  outer  side  of  the  cavernous  sinus,  it  lies  between  the  third  pair  and 
the  ophthalmic  branch  of  the  fifth,  below  the  former  and  above  the  latter  and 
the  sixth;  as  it  enters  the  orbit  it  mounts  above  the  third  and  fifth,  and  is 
therefore  the  highest  nerve  in  the  orbit  both  it  and  the  frontal  being  imme- 
diately beneath  the  periosteum  ; previous  to  entering  the  oblique  muscle  its 
size  is  somewhat  increased. 

The  trigemini,  or  the  fifth  pair,  having  formed  the  semilunar  or  gasserian 


OR  MANUAL  OF  ANATOMY. 


183 


ganglion,  divides  into  three  branches,  the  ophthalmic,  the  superior  and  inferior 
maxillary  nerves. 

The  Ophthalmic  Nerve  passes  along  the  outer  side  of  the  cavernous  sinus 
below  the  third  and  fourth,  and  above  the  sixth;  in  this  situation  it  receives 
some  filaments  from  the  sympathetic  nerve ; as  it  approaches  the  foramen 
lacerum  orbitale,  it  divides  into  three  branches,  the  lachrymal,  frontal,  and 
nasal,  which  are  situated  with  respect  to  the  other  nerves  as  above  described. 

The  lachrymal  nerve,  the  smallest  of  the  three,  passes  forwards  and  out- 
wards to  the  lachrymal  gland  above  the  external  rectus  muscle  and  beneath 
the  periosteum,  but  gives  no  branches  to  this  muscle  ; it  is  surrounded  by  fat 
and  accompanied  by  the  lachrymal  artery ; it  sends  off",  in  this  course,  two 
small  branches,  one  through  the  spheno  maxillary  fissure  to  communicate  with 
the  superior  maxillary  nerve,  and  the  other  through  the  malar-  bone,  to  com- 
municate with  the  facial  nerve ; near  the  gland  the  lachrymal  nerve  enlarges 
and  sends  four  or  five  branches  to  its  inferior  surface,  and  it  then  terminates 
in  several  fine  soft  filaments  on  the  conjunctiva,  lining  the  superior  palpebra 
and  cellular  membrane  between  the  gland  and  malar  bone. 

The  frontal  nerve  enters  the  orbit,  between  th.e  superior  rectus  and  the 
periosteum,  along  with  the  fourth,  but  inferior  and  external  to  it;  it  passes 
forwards  in  a kind  of  groove  on  the  upper  surface  of  the  leyator  palpebra 
muscle;  and  near  the  superciliary  arch  it  divides  into  two  branches,  an  inter- 
nal and  external ; the  internal  or  supra-trochleator  nerve,  the  smaller  branch, 
runs  forwards  and  inwards  above  the  trochlea  of  the  superior  oblique  muscle, 
and  is  distributed  to  the  corrugator  supercilii,  orbicularis  palpebrarum,  and 
occipitO-frontalis  muscles,  also  to  the  integuments  of  the  forehead  and  supe- 
rior eyelid ; it  communicates  with  the  nasal  nerve,  and  sends  one  or  two  small 
filaments  into  the  frontal  sinus.  The  external  branch,  or  the  supra  orbital  or 
proper  frontal  nerve  appears  as  the  continuation  of  the  original  trunk,  both  in 
size  and  in  direction,  it  passes  through  the  superciliary  notch  or  foramen, 
ascends  on  the  forehead,  divides  into-  two  branches  which  subdivide  into 
numerous  filaments,  these  chiefly  ascend  in  the  muscles  and  integuments  of 
the  scalp,  many  of  them  take  a very  long  course,  and  communicate  with  the 
portio  dura,  with  the  occipital  nerves,  and  with  those  from  the  opposite  side. 
Neither  of  these  two  nerves  gives  any  filaments  to  the  muscles  in  the  orbit. 

The  nasal  nerve  separates  from  the'  frontal  behind  the  orbit,  enters  this 
cavity  beneath  that  branch,  and  between  the  two  heads  of  the  external  rectus, 
it  then  runs  obliquely  forwards  and  inwards  above  the  optic  nerve  and  below 
the  superior  rectus  muscle,  and  continues  its  course  along  the  inner  side  of 
the  orbit  below  the  superior  oblique  muscle,  and  here  divides  into  two 
branches,  the  external  or  infra-trochleator  nerve,  and  the  internal  or  the 
nasal ; the  nasal  nerve,  previous  to  its  entrance  into  the  orbit,  is  joined  by  a 
filament  from  the  sympathetic  nerve;  on  the  outer  side  of  the  optic,  and  just 
as  it  enters  this  cavity,  it  gives  off  a delicate  branch  about  an  inch  in  length, 
which  runs  along  the  outer  side  of  the  optic  nerve  to  the  lenticular  ganglion  ; 
as  the  nasal  nerve  passes  over  the  optic  it  gives  off  two  ciliary  nerves.  The 
infra-trochleator  nerve  runs  forwards  beneath  the  pulley  of  the  oblique  muscle 
and  divides  into  several  filaments  which  communicate  with  the  supra-trach- 
leator  nerve,  and  are  distributed  to  the  lachrymal  passages,  and  to  the  integu- 
ments and  muscles  on  the  side  and  dorsum  of  the  nose.  The  internal  branch 


184 


THE  DUBLIN  DISSECTOR, 


or  the  proper  nasal  passes  through  the  anterior  of  the  internal  orbital  holes  into 
the  cranium,  crosses  the  cribriform  plate,  and  descends  by  the  side  of  the 
crista  gal li  into  the  nasal  fossae  where  it  divides  into  posterior  and  anterior 
filaments  ; the  former  are  distributed  to  the  septum,  the  latter  descend  behind 
the  nasal  bones  and  are  lost  in  the  integuments  at  the  tip  of  the  nose.  The 
sixth  pair  of  nerves  should  be  next  dissected,  as  it  is  distributed  along  with 
the  preceding  nerves  in  the  orbit.  h 

Sixth  or  Abducens  Nerve,  after  traversing  the  cavernous  sinus  (where  it 
is  joined  by  branches  from  the  sympathetic  nerve)  on  the  outer  side  of  the 
carotid  artery,  enters  the  orbit  through  the  lower  part  of  the  foramen  lacerum 
between  the  origins  of  the  external  rectus  beneath  the  other  orbital  nerves 
and  above  the  ophthalmic  vein  ; it  then  passes  forwards  and  outwards,  and  is 
distributed  to  the  ocular  surface  of  the  external  rectus  muscle.  The  different 
nerves  in  the  orbit  have  different  offices  to  perform,  viz.  the  second  pair  is  for 
vision,  the  third,  fourth,  and  sixth  pairs  are  for  supplying  muscles,  and  the 
ophthalmic  nerve  is  for  communicating  sensation  to  the  parts  within  and 
without  the  orbit.  The  student  should  next  examine  the  lenticular  or  opthal- 
mic  ganglion;  this  small'body  is  situated  near  the  back  part  of  the  orbit 
between  the  optic  nerve  and  the  external  rectus  muscle ; it  is  of  a reddish 
color  and  surrounded  by  soft  fat;  its  posterior  superior  angle  receives  the 
filament  before  mentioned  from  the  nasal  branch  of  the  ophthalmic;  and  its 
posterior  inferior  angle  receives  the  twig  from  the  inferior  oblique  branch  of 
the  third  pair  ; these  two  nerves  are  described  by  some  as  forming:  this  gang- 
lion ; from  the  anterior  angles  of  this  ganglion  two  fasciculi  of  fine.nerves 
proceed,  termed  the  ciliary ; the  inferior  fasciculus  is  larger  than  the  superior ; 
the  ciliary  nerves  are  about  twenty  in  number,  eight  or  ten  in  the  inferior 
fasciculus,  about  six  in  the  superior,  and  three  or  four  internally,  which  arise 
from  the  nasal  nerve ; the  ciliary  nerves  twine  along  the  surface  of  the  optic 
nerve,  accompanied  by  the  ciliary  arteries,  and  pierce  the  back  part  of  the 
sclerotic  coat,  they  then  become  flat,  and  proceed  forwards  in  the  parallel 
grooves  on  the  inner  surface  of  that  membrane,  with  very  little  connection  to 
the  choroid  coat ; at  the  anterior  part  of  the  eye  they  meet  the  ciliary  liga- 
ment, in  this  substance  most  of  these  nerves  are  lost,  hence  some  consider  this 
as  a ganglion;  on  each  side,  however,  one  or  two  branches  may  be  traced 
through  this  into  the  iris,  in  which  they  divide  into  numerous  filaments  of 
extreme  minuteness.  The  student  should  next  proceed  to  examine  the  supe- 
rior and  inferior  maxillary  nerves,  the  remaining  divisions  of  the  fifth  pair. 
Remove  the  outer  wall  of  the  orbit  with  the  saw  or  hammer,  make  a vertical 
section  of  the  nose  and  face,  and  separate  the  globe  of  the  eye  and  its  muscles 
from  their  attachments  ; below  the  cavity  of  the  orbit  the  superior  maxillary 
nerve  may  be  seen. 

The  Superior  Maxillary  Nerve  passes  from  the  middle  of  the  gasserian 
ganglion  forwards  through  the  foramen  rotundum  into  the  pterygo  maxillary 
fossa;  it  here  sends  off  several  branches,  and  continues  its  course  forwards 
along  the  infra-orbital  canal  to  the  cheek,  where  it  terminates  in  the  infra- 
orbital nerves;  in  the  pterygo-maxillary  fossa  it  first  sends  down  two  small 
branches  along  the  back  part  of  the  superior  maxillary  bone  : these,  after  a 
short  course,  unite  in  a small  triangular  reddish  substance,  called  the  spheno- 
palatine ganglion,  or  the  ganglion  of  Meckel ; this  ganglion  is  embedded  in 


OR  MANUAL  OF  ANATOMY. 


185 


fat,  surrounded  by  the  branches  of  the  internal  maxillary  artery,  and  is  situated 
on  the  external  side  of  the  nasal  plate  of  the  palate  bone,  which  separates  it 
from  the  cavity  of  the  nose,  behind  the  tuberosity  of  the  superior  maxillary 
bone,  and  in  front  of  the  pterygoid  processes.  Three  branches  proceed  from 
Meckel’s  ganglion,  an  inferior,  internal,  and  posterior.  First  the  inferior  or 
the  palatine  nerve  descends  in  the  bony  canal  of  that  name,  sends  some  small 
twigs  through  this  canal  to  the  spongy  bones,  and  near  the  palate  divides  into 
three  filaments,  an  anterior,  middle,  and  posterior:  the  anterior  passes  for- 
wards in  a groove  within  the  alveoli  and  above  the  mucous  membrane,  sup- 
plying the  latter  and  sending  small  branches  into  the  bone  to  the  teeth:  the 
middle  and  posterior  filaments  of  the  palatine  nerve  are  distributed  to  the 
amygdalae,  the  soft  palate,  and  the  uvula.  The  internal  branch,  or  the  spheno- 
palatine nerve  is  very  short,  passes  through  the  spheno-palatine  hole  into  the 
upper  and  back  part  of  the  nose,  and  divides  into  five  or  six  branches;  the 
most  of  these  pass  immediately  into  the  mucous  membrane,  covering  the  supe- 
rior and  middle  spongy  bones,  one  branch  called  the  naso-palatine  nerve,  or 
nerve  of  Cotunnius,  passes  beneath  the  sphenoidal  siuus,  and  descends  ob- 
liquely forwards  along  the  septum  nasi  as  far  as  the  foramen  incisivum,  where 
it  communicates  with  the  anterior  palatine  branches,  and  where  some  anato- 
mists describe  a small  ganglion  (naso-palatine)  to  exist;  this,  however,  can 
seldom  be  distinguished  from  the  surrounding  fat  and  vessels.  The  third  or 
the  posterior  branch  of  Meckel’s  ganglion  is  the  vidian  nerve  ; this  passes 
backwards  through  the  vidian  canal  above  the  internal  pterygoid  plate  and 
sends  some  small  filaments  into  the  sphenoidal  sinus;  it  then  perforates  the 
cartilaginous  substance  that  closes  the  foramen  lacerum  anterius,  enters  the 
cranium,  and  divides  into  two  branches,  an  inferior  and  superior;  the  inferior 
or  carotid  branch  enters  the  cavernous  sinus,  and  joins  the  plexus  formed  in 
this  sinus  around  the  artery  by  the  ascending  branches  of  the  superior  cervical 
ganglion  of  the  sympathetic  ; the  superior  branch  runs  backwards  and  out- 
wards beneath  the  dura  mater  and  gasserian  ganglion  in  a groove  on  the 
petrous  bone,  enters  the  hyatus  Fallopii  in  this  bone,  and  becomes  attached 
to  the  portio  dura  nerve,  which  it  accompanies  as  . far  as  the  back  part 
of  the  tympanum  ; the  vidian  nerve  then  leaves  the  portio  dura,  receives 
the  name  of  corda  tympani , and  enters  the  tympanum  a little  below  the 
pyramid ; it  now  proceeds  forwards  between  the  long  leg  of  the  incus  and 
the  handle  of  the  malleus;  to  the  latter  it  is  firmly  connected;  it  then 
escapes  by  the  hole  in  the  glenoid  fissure  along  with  the  tendon  of  the 
laxator  tympani  muscle ; it  then  runs  downwards,  inwards,  and  forwards, 
joins  the  gustatory  nerve,  and  continues  attached  to  it  as  far  as  the  submaxil- 
lary gland ; it  now  leaves  the  gustatory  nerve  and  unites  with  some  filaments 
from  it  in  the  submaxillary  ganglion,  which  is  situated  near  the  posterior 
edge  of  the  submaxillary  gland,  and  from  which  a number  of  filaments  pro- 
ceed ; these  form  a plexus  which  supplies  this  gland.  The  superior  maxillary 
nerve  immediately  after,  and  sometimes  previous  to  giving  off  the  two 
descending  branches  which  join  the  spheno-palatine  ganglion,  sends  off  the 
orbital  branch,  this  ascends  through  the  spheno-maxillary  fissure  and  divides 
into  two  branches,  the  malar  and  temporal ; the  malar  communicates  with  the 
lachrymal  nerve,  and  is  distributed  to  the  integuments  and  muscles  covering 
the  malar  bone;  the  temporal  branch  also  passes  through  the  malar  bone  into 
24 


186 


THE  DUBLIN  DISSECTOR, 


the  temporal  fossa,  pierces  the  temporal  fascia,  becomes  cutaneous,  and 
joining  some  branches  of  the  fascial  nerve,  it  accompanies  the  temporal  artery, 
and  is  lost  in  the  integuments  of  the  temple  and  head.  The  superior  maxil- 
lary nerve  next  gives  off  the  posterior  dental  nerves  ; these  are  two  or  three 
branches  which  wind  round  the  tuberosity  of  the  maxillary  bone,  enter  small 
foramina,  which  lead  to  the  posterior  alveoli  in  this  bone,  and. supply  the 
molar  teeth;  some  branches  also  supply  the  gums  and  the  buccinator  muscle. 
As  the  infra-orbital  nerve,  which  is  the  last  branch  of  the  superior  maxillary, 
proceeds  along  the  floor  of  the  orbit,  it  sends  off  some  small  filaments  to  the 
fat  and  muscles  in  this  region,  also  the  anterior  dental ; this  descends  along 
the  fore-part  of  the  antrum,  to  the  lining  membrane  of  which  it  gives  some  fine 
filaments  and  is  then  lost  in  several  branches  which  supply  the  canine  and 
incisor  teeth : the  infra-orbital  nerve  then  escapes  through  the  foramen  of  the 
same  name  beneath  the  orbicularis  palpebrarum  and  levator  labii  superioris 
alaquse  nasi  muscles;  it  here  divides  into  several  branches  which  are  distri- 
buted to  the  face,  some  of  these  ascend  to  the  palpebrae,  others  pass  outwards 
to  the  cheek,  and  the  largest  branches  descend  to  the  ala  nasi  and  to  the  upper 
lip  ; these  different  branches  have  frequent  communications  on  the  side  of  the 
face  with  the  portio  dura,  on  the  nose  with  the  nasal  nerves,  and  on  the  buc- 
cinator muscle  they  form  a plexus  with  each  other  and  with  the  buccal  and 
facial  nerves. 

The  Interior  Maxillary  Nerve  ; this,  which  is  the  third  and  largest 
branch  of  the  fifth  pair,  immediately  passes  from  the  ganglion  through  the 
foramen  ovale  into  the  zygomatic  fossa  behind  the  external  pterygoid  muscle, 
where  it  divides  into  two  large  branches,  a superior  or  external,  and  an  infe- 
rior or  internal.  The  inferior  maxillary  nerve  consists  of  two  portions,  one 
is  plexiform,  and  proceeds  from  the  gasserian  ganglion,  the  other  is  concealed 
by  this,  and  consists  of  white  parallel  fibres  which  do  not  pass  through  the 
ganglion;  in  the  zygomatic  fossa  this  small  deep  portion  winds  round  the 
other,  becomes  anterior  to  it,  and  both  unite  inseparably ; the  nerve  then  di- 
vides into  two  branches,  superior  and  inferior  ; the  superior  or  external 
immediately  subdivides  into  the  deep  temporal,  masseteric,  buccal,  and  ptery- 
goid branches  ; the  inferior  or  internal  division  of  the  nerve  is  the  larger,  and 
subdivides  into  the  auricular,  inferior  dental,  and  gustatory  nerves.  First, 
the  deep  temporal  nerves  are  two  in  number,  an  anterior  and  posterior,  they 
ascend  between  the  temporal  bone  and  muscle,  and  are  lost  in  the  latter ; some 
small  branches  escape  through  the  temporal  fascia  and  communicate  w ith  the 
cutaneous  temporal  nerves.  Second,  the  Buccal  nerve  arises  in  general  in 
common  with  one  of  the  last,  it  passes  forwards  and  dowmwmrds  between  the 
pterygoid  muscles  to  the  external  of  which,  and  to  the  temporal,  it  sends  some 
branches,  it  then  passes  between  the  coronoid  process  and  the  buccinator 
muscle,  and  on  the  latter  it  divides  into  several  long  branches  which  form  a 
plexus  on  this  muscle  with  branches  of  the  facial  and  infra-orbital  nerves. 
Third,  the  masseteric  branch  descends  obliquely  backwards  and  outwards 
through  the  sigmoid  notch  of  the  inferior  maxilla,  between  the  temporal  muscle 
and  the  neck  of  the  lower  jaw,  close  to  the  latter,  to  which  also  it  sends  some 
filaments,  it  is  lost  in  the  substance  of  the  masseter  muscle.  Fourth,  the 
Pterygoid  branches  are  two  or  three  delicate  branches  which  descend  to  the 
pterygoid  muscle.  The  deep  portion  of  the  trunk  of  the  inferior  maxillary 


OK  MANUAL  OF  ANATOMY. 


18f 


nerve  may  be  traced  into  these  muscular  branches.  The  three  branches  of 
the  inferior  division  are  the  auricular,  dental,  and  lingual  nerves;  first,  the 
auricular  or  temper o-auricular  branch  ; this  passes  backwards  and  outwards 
behind  the  neck  of  the  lower  jaw,  and  before  the  meatus  auditorius;  it  hei-e 
communicates  with  the  facial  nerve,  and  sends  small  filaments  to-the  meatus 
and  to  the  cartilages  of  the  ear,  also  to  the  articulation  of  the  lower  jaw  ; it 
then  ascends  through  the  parotid  gland  over  the  zygoma  and  divides  into  an 
anterior  and  posterior  branch  which  follow  the  divisions  of  the  temporal  artery, 
communicate  with  the  facial  nerve,  and  are  lost  in  the  integuments  on  the 
anterior  and  lateral  parts  of  the  head.  Second,  the  inferior  dental  nerve 
separates  from  the  gustatory,  and  is  connected  to  it  by  a small  twig;'  it  de- 
scends at  first  between  the  two  pterygoid  muscles,  then  between  the  lower  jaw 
and  the  internal  pterygoid ; it  is  here  separated  from  the  latter  by  the  internal 
lateral  ligament ; about  the  middle  of  the  internal  surface  of  the  ramus  of  the 
jaw  it  sends  off  a small  filament,  the  mylo-hyoid  nerve  this  descends  obliquely* 
forwards,  confined  in  a groove  in  the  bone  by  an  expapsion  from  the  internal 
lateral  ligament ; near  the  chin  it  divides  into  small  branches  for  the  mylo- 
hyoid, genio-hyoid,  and  digastric  muscles.  The  dental  nerve  then  enters  the 
canal  in  the  lower  jaw,  which  extends  from  the  dental  foramen  obliquely  for- 
wards beneath  the  teeth  as  far  as  the  chin;  in  this  course,  this  nerve,  which  is 
accompanied  by  the  dental  vessels,  supplies  each  of  the  molar  and  canine  teeth 
with  soft  delicate  twigs,  and  at  the  mental  foramen  it  divides  into  two  branches, 
one  continues  its  course  within  the  bone  beneath  the  incisor  teeth,  the  other  is 
the  mental  nerve  ; this  escapes  by  the  mental  foramen,  bends  upwards,  and 
divides  in  a radiated  manner  into  several  branches  which  pass  to  the  muscles, 
mucous  membrane,  and  integuments  of  the  lower  lip,  and  communicate  with 
the  facial  nerve.  Third,  the  lingual  or  gustatory  nerve  is  smaller  than  the 
dental,  to  which  it  is  connected  by  a short  branch  which  encloses  a space 
through  which  the  internal  maxillary  artery  passes  ; beyond  this  branch 
of  communication  the  corda  tympani  (which  has  been  before  traced  from 
Meckel’s  ganglion)  joins  the  gustatory  nerve  at  an  acute  angle;  the  latter  is 
increased  in  size  at  this  spot ; the  gustatory  nerve  is  here  situated  between 
the  external  pterygoid  and  the  muscles  of, the  palate  and  pharynx;  it  then 
descends  obliquely  forwards  between  the  internal  pterygoid  and  the  ramus  of 
the  lower  jaw;  it  next  turns  forwards  above  the  submaxillary  gland  and  the 
mylo-hyoid  muscle  and  lies  on  the  mylo-hyoidean  attachment  of  the  superior 
constrictor  of  the  pharynx,  and  on  the  mucous  membrane  of  the  mouth  and  the 
hyo-glossus  muscle,  and  accompanies  the  Whartonian  duct : it  then  ascends 
aboye  the  sublingual  gland  and  becomes  attached  to  the  lateral  and  anterior 
parts  of  the  tongue.  In  this  course  the  gustatory  nerves  gives  off,  1st,  one 
or  two  small  filaments  to  the  internal  pterygoid  muscle;  2nd,  several  to  the 
tonsils,  to  the  muscles  of  the  palate,  to  the  upper  part  of  the  pharynx,  and  to 
the  mucous  membrane  of  the  gums  ; 3rd,  the  corda-tympani  and  some  accom- 
panying filaments  to  form  a plexus  which  supplies  the  sub-maxillary  gland  ; 
4th,  a few  branches  which  descend  along  the  hyo-glossus  muscle  to  communi- 
cate with  the  ninth  or  the  lingual  nerve;  5th,  a fasciculus  of  nerves  to  the 
sublingual  gland,  and  to  the  surrounding  mucous  membrane ; lastly,  at  the 
tongue  it  divides  into  several  branches,  some  pass  deep  into  the  tissue  of  the 
tongue,  others,  which  are  long  and  fine,  mount  towards  its  surface  and  are 


188 


THE  DUBLIN  DISSECTOR. 


lost  in  the  mucous  membrane  and  the  papillse  at  the  anterior  part  of  the 
tongue. 

Facial  Nerve  or  Portio  Dura  of  the  seventh  pair;  as  this  nerve  is  pass- 
ing along  the  aqueduct  of  Fallopius  in  the  temporal  bone  it  receives  superiorly 
the  vidian  nerve;  at  the  back  part  of  the  tympanum  it  sends  off  that  nerve 
again  which  then  receives  the  name  of  corda  tympani,  here  it  also  sends  off 
small  twigs  to  the  tensor  tympani  and  stapedius  muscles ; as  it  escapes  by  the 
stylo-mastoid  foramen  it  gives  off  three  branches,  the  posterior  auricular, 
stylo-hyoid,  and  sub-mastoid;  the  first,,  or  the  posterior  auricular,  bends  up- 
wards and  backwards  behind  the  cartilage  of  the  ear,  to  which  it  sends  several 
long  branches,  others  also  pass  backwards  to  the  integuments  covering  the 
mastoid  process  and  occipital  bone ; the  second,  or  the  slylo-hyoid  nerve,  is 
distributed  to  the  digastric  and  styloid  muscles,  and  anastomoses  with  the 
sympathetic  and  glosso-pharyngeal  nerves;  the  third;  or  the  sub-mastoid 
branch,  perforates  the  posterior  belly  of  the  digastric,  supplies  it  with  several 
filaments,  and  then  coinmunicates  with  the  glosso-pharyngeal  nerve  around 
the  jugular  vein  close  to  the  base  of  the  cranium,  other  filaments  descend  and 
join  the  laryngeal  branches  of  the  pneumo-gastric  nerve.  The  fascial  nerve 
then  turns  forwards  across  the  external  carotid  artery  and  through  the  parotid 
gland;  in  this  substance  it  divides  into  two  large  branches,  the  superior  or 
larger  is  called  temporo-facial ; the  inferior,  which  is  smaller,  the  cervico- 
facial; these  two  branches  take  different  directions,  but  are  still  connected 
together  by  cross  branches  which  interlace  with  each  other  in  a plexiform 
manner;  this  plexus  is  named  parotidean  plexus,  or  pes  anserinus.  The  tem- 
poro-facial nerve  ascends  obliquely  forwards  across  the  neck  of  the  lower 
jaw ; it  first  communicates  with  the  auricular  branch  of  the  inferior  maxillary 
nerve,  and  then  divides  into  three  fasciculi,  the  temporal,  malar,  and  buccal; 
these  nerves  take  that  course  which  their  name  implies ; they  are  all  remark- 
able for  the  plexiform  arrangement  of  their  branches,  and  for  their  frequent 
communications  with  each  other,  and  with  the  three  divisions  of  the  fifth  pair, 
which  ai  e distributed  to  the  face.  The  cervico -facial  nerve  descends  obliquely 
forwards  through  the  parotid  gland  towards  the  angle  of  the  jaw,  where  it  is 
only  covered  by  the  skin  and  pljiysma;  this  nerve  also  divides  into  many 
branches,  which  may  be  arranged  in  three  fasciculi,  the  maxillary,  the  sub- 
maxillary, and  the  cervical ; the  first,  or  the  maxillary,  cross  the  ramus  of  the 
jaw  and  the  massetdr  muscle,  and  communicate  in  the  muscles  of  the  lower 
lip  with  the  mental  nerve,  and  with  the  superior  division  of  the  seventh ; the 
second,  or  sub-maxillary , course  along  the  base  of  the  jaw,  sending  filaments 
to  the  integuments  and  superficial  muscles,  these  also  communicate  at  the 
chin  with  the  mental  nerve;  the  third,  or  cervical  branches,  are  very  long  and 
numerous;  they  are  distributed  to  the  platysma  and  to  the  superficial  muscles 
of  the  neck,  and  communicate  with  several  filaments  of  the  cervical  plexus. 
The  portio  dura  nerve  has  been  ingeniously  supposed  by  Mr.  Bell  to  be  the 
nerve  that  excites  the  muscles  of  the  face  in-particular  conditions  of  respira- 
tion and  in  the  expression  of  passion,  &c.,  hence  he  has  named  it  the  respira- 
tory nerve  of  the  face  ; others  consider  the  portio  dura  as  the  exclusive  motor 
nerve  of  the  face. 

The  Auditory  Nerve  or  Portio  Mollis  of  the  seventh  pair;  this  nerve 
separates  from  the  portio  dura  at  the  bottom  of  the  meatus  auditorius  internus. 


OR  MANUAL  OF  ANATOMY. 


189 


and  then  divides,  into  two  branches,  an  anterior  and  posterior ; the  anterior 
passes  forwards  to  the  cochlea,  penetrates  through  many  small  openings,  and 
is  distributed  to  the  membrane  covering  its  spiral  lamina,  and  to  that  lining 
the  canal  on  its  axis : the  posterior  branch  passes  outwards,  forms  a gray 
swelling,  from  which  proceed  several  filaments  to  supply  the  membrane  lining 
the  vestibule  and  semi-circular  canals. — (See  Anatomy  of  the  Ear.) 

Glosso-pharangeal  Nerve,  or  the  first  branch  of  tlm  eighth  pair;  this 
small  nerve  passes  through  the  foramen  lacerum  posterius  by  a distinct  canal, 
it  then  passes  downwards  and  forwards  anterior  and  internal  to  the  jugular 
vein  and  carotid  artery,  and  behind  the  stylo-pharyngeus  muscle ; it  then 
winds  round  this  muscle  to  its  fore  part  and  descends  obliquely  inwards  be- 
tween it  and  the  stylo-glossus  to  the  posterior  and  lateral  parts  of  the  tongue ; 
in  this  course  this  nerve  forms  an  arch  nearly  parallel  to  that  which  the  gus- 
tatory and  lingual  nerveS  describe ; the  glosso-pharyngeal  is  smaller  than 
either  of  these  nerves;  it  is  situated  between  them,  but  deeper  than  either; 
and  has  very  little,  if  any,  communication  with  them.  As  this  nerve  leaves 
the  cranium  it  sends  one  or  two  small  twigs  into  the  temporal  bone,  these 
communicate  with  the  carotid  plexus  in  the  cavernous  sinus;  it  is  next 
attached  to  the  facial,  pneu mo-gastric,  and  sympathetic  nerves  by  small  fila- 
ments, which  are  connected  together  by  loose  reddish  cellular  membrane,  and 
entangled  with  several  small  vessels.  This  nerve  next  gives  off  some  branches 
to  the  pharyngeal  plexus,  some  of  these  descend  along  the  neck,  and  unite 
with  the  sympathetic  and  cardiac  nerves,  others  ascend  to  the  amygdala,  and 
assist  in  forming  the  tonsillitic  plexus ; as  it  approaches  the  pharynx,  this 
nerve  gives  several  branches  to  the  stylo-pharyngeus  and  hyo-glossus  muscles, 
also  to  the  superior  and  middle  constrictors  of  the  pharynx ; several  filaments 
pass  between  these  to  the  mucous  membrane  of  the  pharynx  and  fauces,  also 
to  the  folds  or  arches  of  the  palate  and  to  the  epiglottis ; the  remaining 
branches  of  the  glosso-pharyngeal  nerve  are  distributed  to  the  muscular  sub- 
stance, papillae,  and  mucous  membrane  at  the  root  of  the  tongue. 

Pneumo-gastric  Nerve,  or  nervus  vagus;  this  large  nerve  passes  through 
the  foramen  lacerum  in  a fibrous  canal  distinct  from  the  last  described  nerve, 
and  anterior  to  the  jugular  vein  ; it  then  communicates  with  the  spinal  acces- 
sory,  glosso-pharyngeal,  lingual,  and  sympathetic  nerves;  to  all  these  it  is 
closely  connected,  and  the  nerve  here  has  the  compact  appearance,  and  some- 
times the  grayish  tint  of  a ganglion ; at  first  it  is  placed  anterior  to  the  vein 
and  to  the  lingual  nerve ; it  soon,  however,  passes  behind  both  and  opposite 
the  atlas,  the  vein  separates  it  from  the  glosso-pharyngeal  nerve  which  lies 
anterior  to  that  vessel ; the  vagus  then  descends  along  the  fore-part  of  the 
neck  enclosed  in  the  sheath  of  the  carotid  artery  and  jugular  vein:  in  this 
sheath  it  is  placed  between  these  vessels,  rather  behind  and  more  closely  con- 
nected to  the  vein ; on  the  right  side  this  nerve  enters  the  thorax  between  the 
subclavian  vein  and  artery,  crossing  the  latter  at  right  angles ; on  the  left  side 
it  is  also  anterior  but  nearly  parallel  to  the  subclavian  artery,  a little  below 
which  it  crosses  obliquely  the  back  part  of  the  arch  of  the  aorta;  in  the  tho- 
rax these  nerves  descend  at  first  obliquely  backwards  behind  the  roots  of  the 
lungs  and  enter  the  posterior  mediastinum,  they  then  descend  along  the  oeso- 
phagus through  the  diaphragm  and  terminate  on  the  stomach.  Each  pneumo- 
gastric  nerve  gives  off  the  following  branches;  they  may  be  divided  into 


190 


THE  DUBLIN  DISSECTOR, 


cervical,  thoracic,  and  abdominal ; the  cervical  branches  are,  the  pharyngeal, 
superior  laryngeal,  cardiac  and  recurrent  or  inferior  laryngeal.  First,  the 
pharyngeal  nerve  arises  from  the  vagus  near  the  base  of  the  cranium,  and 
soon  receives  a twig  from  the  spinal  accessory;  it  descends  obliquely  inwards 
behind  the  carotid  artery  to  the  side  of  the  pharynx,  divides  into  several 
branches,  which  communicate  with  those  from  the  glosso-pharyngeal,  laryn- 
geal, and  sympathetic;  all  these  branches  form  the  pharyngeal  plexus;  this 
plexus  extends  along  the  side  of  the  middle  and  upper  constrictor,  and  sends 
numerous  filaments  to  each  of  these  muscles,  and  to  the  mucous  membrane 
of  the  pharynx  and  fauces.  Second,  the  superior  laryngeal  nerve  arises  a 
little  below  the  last;  it  runs  in  an  arched  manner  downwards  and  forwards 
behind  the  internal  carotid  artery,  and  below  the  superior  cervical  ganglion, 
with  which  it  communicates,  as  also  with  the  lingual  nerve;  it  sends  several 
filaments  to  the  pharyngeal  plexus  and  then  ditides  into  two  branches,  ex* 
ternal  and  internal ; the  external  is  distributed  to  the  sterno  and  hyo-thyroid, 
and  to  the  other  superficial  muscles,  also  to  the  thyroid  gland  and  to  the  car- 
tilages of  the  larynx;  the  internal  perforates  the  thyro-hyoid  membrane  and 
divides  into  numerous  branches,  many  of  these  go  to  the  anterior  surface  of 
the  epiglottis,  to  the  glands  and'  mucous  membrane  connected  with  it,  also  to 
the  arytenoid  glands  and  muscles;  one  long  filament  descends  obliquely  for- 
wards along  the  side  of  the  larynx  beneath  the  thyroid  cartilage  and  supplies 
the  crico-thyroid  muscle.  * As  the  vagus  descends  it  frequently  gives  off  fine 
filaments  to  the  carotid  artery,  and  to  unite  with  the  sympathetic  and  with  the 
cervical  nerves ; a little  above  the  arteria  innominata  the  right  vagus  gives  off 
its  cardiac  branches,  these  join  the  cardiac  nerves  from  the  sympathetic  ; the 
nerve  of  the  left  side  does  not  send  off  so  many  or  such  large  branches  as  that 
on  the  right  side ; on  the  left  side  they  accompany  the  carotid  artery  to  the 
arch  of  the  aorta,  expand  over  it,  and  then  join  the  cardiac  plexus.  Inferior 
laryngeal  nerve,  or  recurrent;  that  on  the  right  side  curves  round  the  subcla- 
vian artery,  ascends  obliquely  inwards  behind  the  carotid  along  the  side  of 
the  trachea  to  the  larynx;  at  its  origin  it  gives  off  some  cardiac  filaments, 
afterwards  some  branches  to  the  fore-|Jhrt  of  the  trachea  and  the  thyroid 
gland;  it  then  supplies  the  lower  part  of  the  pharynx  and  ends  in  the  poste- 
rior and  lateral  crico-arytenoid  and  in  the  thvro-arytenoid  muscles,  also  in 
the  mucous  membrane  of  the  larynx  on  which  it  communicates  with  the  supe- 
rior laryngeal  nerve.  The  recurrent  nerve  on  the  left  side  is  much  longer,  it 
curves  round  the  arch  of  the  aorta  behind  the  ligamentous  remains  of  the 
ductus  arteriosus;  it  gives  off  several  cardiac  and  pulmonary  branches,  and 
then  ascends  alopg  the  oesophagus  and  terminates  in  a similar  manner  to  that 
on  the  right  side.  The  pneumo -gastric  nerves  in  their  course  through  the 
thorax  send  off  the  pulmonary  and  oesophageal  nerves.  The  pulmonary 
branches  arise  from  each  vagus  a little  above  the  roots  of  each  lung ; a few  of 
these  branches  pass  to  the  fore-part  of  the  bronchial  tubes  and  form  there  a 
small  plexus  termed  the  anterior  pulmonary  plexus ; this  plexus  communi- 
cates with  the  phrenic  nerve  and  sends  its  fine  filaments  along  the  pulmonary 
vessels  to  the  lungs  and  pericardium;  the»greater  number  of  these  pulmonic 
branches  pass  behind  the  bronchial  tubes  to  the  posterior  pulmonic  plexus ; 
near  the  root  of  the  lung  each  vagus  increases  in  size,  its  fibres  divide,  sub- 
divide, and  unite  in  an  areolar  or  plexiform  manner,  forming  the  posterior 


OR  MANUAL  OF  ANATOMY. 


191 


pulmonic  plexus  ; this  plexus  is  very  large,  lymphatic  glands  and  vessels  are 
entangled  in  it,  and  several  branches  from  the  sympathetic  join  it;  its  nu- 
merous filaments  accompany  the  bronchial  tubes  closely  through  the  substance 
of  the  lungs.  Below  the  root  of  each  lung  the  fibres  of  each  vagus  again 
approximate,  and  these  nerves  now  become  attached  to  the  oesophagus,  along 
which  they  descend  to  the  stomach,  the  left  on  its  anterior,  the  right  on  its 
posterior  surface ; they  frequently  communicate  with  each  other  so  as  to  en- 
circle the  oesophagus  with  a sort  of  plexus,  which  is  named  the  oesophageal 
plexus,  or  plexus  guise.  On  the  stomach  the  right  vagus,  which  is  the  largest, 
passes  behind  the  cardiac  orifice,  to  which  it  sends  several  small  branches 
which  unite  with  some  from  the  left  or  anterior  nerve ; these  form  the  cardiac 
plexus  which  encircles  this  part  of  the  stomach ; it  then  sends  many  long  fila- 
ments to  the  muscular  and  mucous  coats  of  the  stomach,  these  communicate 
with  the  solar  plexus,  also  with  the  splenic  and  hepatiG.  The  left  or  anterior 
vagus  spreads  its  branches  along  the  anterior  surface  of  the  stomach  and  the 
lesser  curvature ; several  of  these  pass  along  the  lesser  omentum  to  the  liver. 

The  Nervus  Accessorius,  or  the  third  branch  of  the  eighth  pair;  this  nerve, 
in  passing  through  the  foramen  lacerum,  is  closely  connected  to  the  vagus ; 
below  the  base  of  the  cranium  it  communicates  with  the  8th,  9th,  and  sympa- 
thetic nerves,  passes  behind  the  internal  jugular  vein,  perforates  the  upper 
third  of  the  sterno-mastoid  muscle,  to  which  it  sends  some  filaments,  it  then 
communicates  freely  with  the  cervical  plexus,  is  increased  in  size,  and  termi- 
nates in  the  trapezius  muscle  and  the  integuments. 

The  Lingual  Nerve,  or  the  ninth  pair,  on  escaping  from  the  condyloid 
foramen  communicates  with  the  eighth  pair,  the  sympathetic,  and  the  nervous 
arch  or  loop  of  the  atlas  ; it  is  at  first  posterior  to  the  vessels  and  nerves  in 
this  situation,  it  then  descends  along  their  outer  side,  soon  turns  forwards, 
and  becomes  superficial  to  them  ; it  then  takes  the  arched  course  of  the  digas- 
tric muscle  across  the  neck,  parallel  but  superficial  to  the  lingual  artery, 
and  arriving  at  the  side  of  the  base  of  the  tongue  above  the  os  hyoides,  it 
passes  above  the  mylo-hyoid  muscle  and  lies  on  the  middle  constrictor  and  on 
the  hyo-glessus,  at  the  anterior  edge  of  which  it  divides  into  several  filaments, 
some  of  these  plunge  into  the  lingualis  and  genio-glossus  muscles,  others  con- 
tinue on  to  the  point  of  the  tongue,  communicating  with  each  other  and  sup- 
plying the  muscular  substance  of  this  organ.  As  the  lingual  nerve  is  bending 
across  the  cheek  below  the  digastric  tendon  it  sends  off  a considerable  branch, 
the  clescendens  colli,  or  noni;  this  nerve  frequently  receives  a filament  from 
the  pneumo-gastric ; it  descends  along  the  fore- part  of  the  sheath  of  the  caro- 
tid artery  ; about  the  middle  of  the  neck  rt  is  joined  by  the  internal  descend- 
ing branches  of  the  cervical  plexus,  with  which  it  forms  a small  triangular 
plexus,  the  branches  of  which  pass  to  the  omo  and  sterno-hyoid  and  thyroid 
muscles ; on  the  latter  some  filaments  descend  into  the  chest.  Near  the  os 
hyoides  the  lingual  nerve  sends  some  filaments  to  the  constrictors  of  the  pha- 
rynx and  stylo  pharyngeus,  also  one  to  the  thyro-hyoid  muscle ; on  the  surface 
of  the  hyo-glossus  it  gives  off  several  branches  to  the  surrounding  muscles, 
some  also  communicate  with  the  gustatory  branch  of  the  fifth  pair ; the  lingual 
nerve  then  terminates  chiefly  in  the  genio-hyo-  glossus  muscle. 


192 


THE  DUBLIN  DISSECTOR, 


§ 2. — Dissection  of  the  Spinal  Nerves. 

There  are  eight  cervical  nerves,  the  first  passes  out  above  the  atlas,  and  is 
named  the  sub-occipital,  the  eighth  passes  out  above  the  first  dorsal  vertebra. 
All  these  nerves  immediately  outside  the  inter-vertebral  foramina,  divide  into 
a posterior  and  an  anterior  branch;  the  posterior  of  each  is  smaller' than  the 
anterior,  with  the  exception  of  the  second  cervical  nerve,  whose  posterior 
branch  is  very  considerable,  as  it  not  only  supplies  the  adjacent  muscles,  but 
also  accompanies  the  occipital  artery  and  its  ramifications  in  the  scalp;  the 
posterior  branches  of  the  other  cervical  nerves  are  small,  they  all  communi- 
cate with  each  other,  and  are  distributed  to  the  integuments  and  muscles  on 
the  back  part  of  the  neck.  The  anterior  branch  of  the  first  or  the  sub-occipital 
passes  forwards  above  the  transverse  process  of  the  atlas,  and  supplies  the 
adjoining  small  recti  muscles,  then  descends  before  the  atlas,  and  unites  with 
the  anterior  division  of  the  second  cervical,  so  as  to  encircle  that  bone  with  a 
nervous  loop;  in  this  course' the  sub-occipital  is  united  by  branches  to  the 
eighth  and  ninth,  and  to  the  superior  ganglion  of  the  sympathetic  nerve ; with 
the  latter  nerve  the  anterior  branches  of  all  the  spinal  nerves  regularly  com- 
municate. The  anterior  branch  of  the  second  having  received  that  from  the 
first,  descends  and  joins  the  anterior  division  of  the  fhird,  this  in  like  manner 
is  connected  to  the  fourth ; these  anastomoses  between  the  anterior  branches 
of  the  four  superior  cervical  nerves  constitute  the  cervical  plexus  ; the  ante- 
rior branches  of  the  four  inferior  cervical  are  much  larger  than  those  of  the 
superior;  they  are  united  in  like  manner  to  each  other,  and  to  the  anterior 
branch  of  the  first  dorsal,  and  constitute  the  brachial  plexus;  these  two 
plexuses  and  their  branches  the  student  may  next  dissect. 

The  Cervical  Plexus  is  formed  by  the  anterior  branches  of  the  four  supe- 
rior cervical  nerves,  which  join  each  other  in  arches,  from  the  convexities  of 
which  branches  arise  that  again  join  in  a similar  manner,  a quantity  of  cellu- 
lar membrane  is  entangled  in  the  areolae  between  these ; this  plexus  is  situated 
on  the  side  of  the  neck,  on  a level  with  the  2d,  3d,  and  4th  vertebrae,  between 
the  sterno  mastoid  and  trapezius  muscles ; it  sends  oft’  several  branches  which 
may  be  classed  into  ascending  and  descending;  the  former  consist  of  super- 
ficial and  deep,  the  latter  of  internal  and  external : the  ascending  superficial 
branches  are  two  or  thyee  in  number,  they  ascend  obliquely  forwards  over  the 
sterno-mastoid  muscle,  supply  the  platysma  and  integuments  over  the  parotid 
gland,  also  on  the  ear  and  on  the  side  and  back  part  of  the  head,  and  commu- 
nicate freely  with  the  portio  dura  of  the  7th  pair  of  nerves;  one  of  these  is 
much  larger  than  the  others,  is  named  superficialis , or  ascendens  colli,  it 
may  be  traced  chiefly  from  the  third  cervical,  and  is  lost  neat;  the  ear  alid  in 
the  parotid  gland ; this  nerve  accompanies  the  external  jugular  vein.  The 
deep  ascending  branches  of  the  plexus,  are  small  nerves  which  supply  the 
sterno-mastoid,  digastric,  splenius,  and  adjacent  muscles,  and  communicate 
with  the  neighboring  nerves.  The  descending  branches  are  internal  and 
external,  the  internal  are  twro,  a superficial  and  a deep;  the  superficial 
internal  descending  branch  joins  the  descendens  noni,  and  assists  it  in  sup- 
plying the  superficial  muscles  on  the  fore-part  of  the  neck.  The  deep 
internal  descending  branch  is  the  phrenic  nerve:  this  arises  from  the  lower 


OR  MANUAL  OF  ANATOMY. 


193- 


part  of  the  plexus,  chiefly  from  the  4th  cervical,  it  has  also  in  general  a fila- 
ment or  two  from  the  brachial  plexus ; the  phrenic  nerve,  or,  as  it  is  also 
named,  the  internal  respiratory  nerve  descends  obliquely  inwards,  on  the 
anterior  scalenus  muscle,  at  the  lower  part  of  the  neck  it  communicates  with 
the  lower  cervical  ganglion,  and  often  with  the  vagus  or  its  recurrent,  it  then 
enters  the  thorax  between  the  subclavian  vein  and  artery,  and  descends  to  the 
diaphragm  on  the  side  of  the  pericardium  between  it  and  the  pleura ; the  right 
phrenic  is  nearly  perpendicular,  the  left  takes  an  oblique  course  round  the 
apex  of  the  heart,  it  is  therefore  longer  and  lies  more  posterior  than  the  right. 
On  the  diaphragm  these  nerves  divide  into  several  branches,  some  of  which 
ramify  on  the  superior  surface  of  that  muscle,  others  on  its  inferior  accompa- 
nying the  phrenic  vessels.  These  branches  on  the  right  side  send  some  fila- 
ments to  the  inferior  vena  cava  and  to  the  liver,  and  unite  with  the  nerves  of 
this  organ  and  with  those  of  the  stomach ; on  the  left  side  the  phrenic  nerve 
sends  some  filaments  to  the  oesophagus  and  stomach,  these  communicate  with 
the  vagus  and  solar  plexus.  The  phrenic  nerve  can  be  traced  into  the  spinal 
canal,  and  be  seen  to  arise  distinctly  from  the  side  of  the  spinal  marrow.  The 
external  descending  branches  of  the  cervical  plexus  are  numerous,  some  are 
superficial,  others  deep,  the  superficial  descend  to  the  clavicle  and  acromion 
process,  supply  the  superficial  muscles  in  their  course,  and  terminate  in  the 
pectoral  and  deltoid  muscles  and  in  the  integuments;  the  deep  branches 
descend  behind  the  clavicle,  supply  the  deep  muscles  on  the  side  of  the  neck 
and  those  connected  to  the  scapula ; one  of  these  branches  is  remarkable  for 
its  length,  it  is  of  the  same  size  as  the  phrenic,  and  is  named  the  external 
respiratory  nerve  of  the  trunk;  this  nerve  proceeds  from  the  back  part  of  the 
plexus,  chiefly  from  the  4th  cervical,  it  has  also  filaments  connecting  it  to 
the  3d  and  2d,  and  to  the  phrenic,  it  descends  behind  the  scaleni  muscles  and 
beneath  the  trapezius  and  levator  anguli  scapulae,  and  is  almost  exclusively 
distributed  to  the  serratus  magnus  muscle. 

The  Brachial  Plexus  is  formed  by  the  junction  of  the  anterior  branches  of 
the  5th,  6th,  7th,  and  8th  cervical,  and  of  the  1st  dorsal;  this  plexus  is 
broad  and  flat,  the  nerves  forming  it  are  very  large,  particularly  the  inferior ; 
it  is  situated  at  the  inferior  and  lateral  part  of  the  neck,  between  the  scaleni 
muscles  and  above  the  subclavian  artery,  it  then  descends  obliquely  outwards 
beneath  the  clavicle  and  subclavian  muscle  and  over  the  first  rib,  into  the 
axilla,  where  it  rests  on  the  serratus  magnus  behind  the  axillary  artery  and 
vein.  The  5th  and  6th  cervical  unite  first,  the  7th  cervical  runs  alone  for 
some  distance,  the  8th  cervical  and  1st  dorsal  unite  immediately,  so  that  at 
first  this  plexus  consists  of  three  roots,  these  however  soon  unite,  and  in  the 
axilla  again  separate  and  subdivide  into  several  branches  : the  branches  of  this 
plexus  are  the  thoracic,  supra  and  sub-scapular,  the  internal  and  external 
cutaneous,  the  median,  ulnar,  musculo-spiral,  and  circumflex.  The  thoracic 
branches  arise  principally  from  the  upper  part  of  the  plexus,  are  four  or  five  in 
number,  and  divide  into  anterior  and  posterior,  the  former  descend  behind  the 
clavicle  in  front  of  the  axillary  artery,  subdivide  into  branches  which  accom- 
pany the  thoracic  arteries,  supply  the  pectoral  muscles,  and  communicate  with 
cutaneous  branches  from  the  intercostal  nerves;  the  posterior  thoracic  nerves 
descend  behind  the  vessels  to  the  serratus  magnus,  posterior  scalenus  and 
rhomboid  muscles.  The  supra  scapular  nerve  arises  from  the  upper  division 
25 


194 


THE  DUBLIN  DISSECTOR, 


of  the  plexus,  descends  obliquely  backwards,  parallel  to  the  omo-hyoid  muscle 
to  the  superior  costa  of  the  scapula,  passes  beneath  the  posterior  ligament 
which  converts  the  notch  in  this  part  of  the  bone  into  a foramen,  it  then  gives 
off  a considerable  branch  to  the  supra  spinatus  muscle,  and  proceeds  beneath 
the  acromion  process  and  behind  the  neck  of  the  scapula  to -the  infra-spinous 
fossa,  where  it  is  distributed  to  the  infra-spinatus  and  teres  muscles.  The 
sub-scapular  nerves  are  three  or  four  in  number,  they  arise  from  different  parts, 
but  chiefly  from  the  upper  division  of  the  plexus,  they  descend  behind  the 
vessels  and  ramify  in  the  sub-scapular  latissiinus  dorsi,  and  teres  majormuscles. 
Internal  cutaneous  nerve,  is  a long  but  delicate  nerve,  it  arises  out  of  the 
lower  division  of  the  plexus,  descends  nearly  perpendicularly  along  the  inner 
side  of  the  arm,  at  first  covered  by  the  brachial  aponeurosis,  near  the  elbow 
it  becomes  cutaneous,  and  runs  parallel  to  the  basilic  vein,  and  divides  into 
two  branches,  an  external  and  internal ; the  external  passes  along  the  border 
of  the  biceps  over  the  bend  of  the  elbow  to  the  fore-arm,  where  it  divides  into 
several  filaments,  some  of  which  descend  in  the  integuments  as  low  as  the 
wrist,  and  communicate  with  the  other  cutaneous  uerves;  this  branch  gene- 
rally crosses  the  median  basilic  vein,  in  some  it  lies  superficial  to  it,  in  others 
behind  it;  the  internal  branch  descends  towards  the  internal  condyle,  and 
divides  into  several  filaments,  some  of  which  descend  along  the  inner,  and 
others  along  the  posterior  part  of  the  fore-arm,  they  all  terminate  in  the  integu- 
ments. External  cutaneous  nerve,  or  musculo -cutaneous  or  pcrforans  casserii 
is  larger  than  the  last,  and  arises  from  the  upper  division  of  the  plexus,  it  de- 
scends obliquely  outwards,  through  the  fibres  of  the  coraco-brachialis,  and 
between  the  brachiaeus  anticus  and  the  biceps,  it  then  descends  along  the  outer 
border  of  the  latter  to  the  bend  of  the  elbow,  pierces  the  aponeurosis,  be- 
comes cutaneous,  and  descends  along  the  radial  side  of  the  fore-arm  to 
the  wrist;  in  the  arm  this  nerve  gives  muscular  branches  to  the  coraco- 
brachialis,  biceps,  and  brachiaeus  anticus,  in  the  latter  muscle  it  frequently 
communicates  with  the  median  nerve.  At  the  elbowT  this  nerve  is  situated 
between  the  biceps  and  supinator  longus,  and  behind  the  cephalic  vein,  along 
the  fore-arm  it  accompanies  this  vein,  and  is  often  superficial  to  it ; near  the 
wrist  this  nerve  divides  into  an  anterior  and  posterior  branch,  the  former 
passes  to  the  ball  of  the  thumb  and  palm  of  the  hand,  the  latter  to  its  dorsum. 
Median  or  brachial  nerve  is  the  largest  branch  of  the  plexus,  it  generally 
arises  by  two  roots,  a small  external  one,  which  is  in  common  with  the  exter- 
nal cutaneous  from  the  upper  part  of  the  plexus,  and  a large  internal  one  from 
the  lower  division  of  the  plexus ; the  brachial  artery  in  general  separates  these 
two  roots,  which  soon  unite  into  one  thick  cord  ; it  descends  obliquely  out- 
wards along  the  inner  edge  of  the  biceps,  as  far  as  the  bend  of  the  elbow,  and 
in  this  part  of  its  course  it  is  covered  only  by  the  skin  of  the  fascia,  situated 
rather  to  the  outer  side  of  the  artery  above,  crossing  over  it  about  the  middle 
of  the  arm,  and  to  its  ulnar  side  below ; at  the  bend  of  the  elbow  it  passes  deep 
between  the  supinator  longus  and  pronator  teres,  and  on  the  brachiaeus  anti- 
cus, perforates  the  pronator  and  then  descends  along  the  middle  of  the  fore- 
arm, between  the  superficial  and  deep  flexors,  passes  beneath  the  annular 
ligament  of  the  carpus,  where  its  size  is  increased,  and  terminates  in  the  palm 
of  the  hand  by  dividing  into  five  branches.  In  the  arm  the  median  nerve  give 
but  few  branches,  these  are  small  and  unimportant ; in  the  fore-arm  it  sends 


OR  MANUAL  OF  ANATOMY. 


195 


several  considerable  branches  to  the  superficial  and  deep  pronators  and 
flexors,  but  not  to  the  supinators,  a little  below  the  elbow  it  also  gives  off  the 
anterior  inter-osseal  nerve,  this  accompanies  the  artery  of  the  same  name, 
along  the  anterior  surface  of  the  inter-osseous  membrane,  and  supplies  the 
deep  flexors ; at  the  pronator  quadratus  it  divides  into  two  branches,  one  to 
supply  that  muscle,  the  other  traverses  the  inter-osseous  space,  and  is  lost  on 
the  dorsum  of  the  carpus  and  metacarpus;  a little  above  the  wrist, the  median 
nerve  gives  off  a superficial  branch,  which  passes  over  the  annular  ligament, 
and  is  lost  in  the  integuments;  in  the  palm  of  the  hand,  the  median  nerve 
divides  into  five  digital  branches,  the  two  first  pass  one  along  either  side  of  the 
thumb,  the  third  goes  to  the  radial  side  of  the  index-finger,  the  fourth  supplies 
the  opposed  sides  of  the  index  and  middle  finger,  and  the  fifth,  which  isjoined 
by  a small  branch  from  the  ulnar  nerve,  supplies  the  opposed  sides  of  the  mid- 
dle and  ring  fingers ; these  digital  branches  in  the  palm  of  the  hand  are  super- 
ficial to  the  tendons,  and  form  an  arch  nearly  parallel  to  that  formed  by  the 
ulnar  artery,  the  branches  of  the  latter  and  the  digital  nerves  then  run  toge- 
ther to  the  extremity  of  each  finger;  in  this  course  they  supply  the  lumbri- 
cales,  the  integuments  of  the  hand  and  fingers,  and  near  the  last  phalanx  of 
each  the  nerves  enlarge  and  become  red  and  soft,  and  divide  into  numerous 
fine  branches,  which  are  lost  in  the  papillae  of  the  cutis.  Ulnar  nerve  arises 
from  the  lower  part  of  the  plexus,  descends  obliquely  backwards  along  the 
biceps,  and  behind  the  elbow  joint,  through  the  groove  between  the  inner  con- 
dyle and  the  olecranon  process ; it  then  passes  forwards,  and  descends  along 
the  ulnar  side  of  the  fore-arm  to  the  carpus,  and  passing  over  the  annular 
ligament  close  to  the  pisiform  form,  ends  in  the  palm  of  the  hand,  in  two 
branches,  a superficial  and  a deep.  In  the  arm  this  nerve  is  superficial,  and 
gives  off  a few  branches  to  the  triceps  and  to  the  skin  ; in  the  fore-arm  it  lies 
on  the  flexor  profundus,  and  between  the  flexor  sublimis  and  ulnaris  ; to  these 
muscles,  particularly  the  latter,  it  sends  several  filaments  ; a little  above  the 
wrist  it  gives  off"  the  dorsalis  carpi  ulnaris,  a large  branch  which  winds  round 
the  ulna  to  the  back  of  the  hand,  and  divides  into  several  long  branches  which 
are  lost  in  the  integuments  of  that  region  and  of  the  three  inner  fingers.  Of  the 
terminating  branches  of  the  ulnar  nerve,  the  superficial  is  the  larger,  it  divides 
into  three  branches,  which  supply  the  muscles  and  both  sides  of  the  little  fin- 
ger, also  the  ulnar  side  of  the  ring  finger;  the  deep  palmar  branch  passes  be- 
neath the  flexor  tendons,  runs  across  the  metacarpus,  and  assists  in  forming  a 
deep  palmar  arch,  the  branches  of  which  are  lost  in  the  inter-ossei  muscles. 
Musculo -spiral  nerve,  is  a very  large  nerve,  it  proceeds  from  the  middle  and 
lower  divisions  of  the  plexus,  descends  obliquely  backwards  and  outwards 
between  the  three  portions  of  the  triceps,  x-ound  the  humerus  to  its  external 
side,  it  then  turns  obliquely  forwards  and  downwards  towards  the  elbow 
between  the  supinator  longus  and  the  brachireus  anticus,  and  there  divides 
into  two  branches,  an  anterior  or  radial  branch,  a posterior  or  inter-osseal 
branch.  In  its  course  down  the  arm  this  nerve  sends  several  branches  to  the 
triceps,  a little  above  the  outer  condyle  it  gives  off  a large  cutaneous  branch, 
which  branch  descends  along  the  radial  side  of  the  fore-arm  to  the  thumb  ; at 
the  bend  of  the  elbow  this  nerve  sends  several  branches  to  the  long  and  short 
supinators,  also  to  the  extensors  of  the  carpus  ; on  the  surface  of  the  supinator 
brevis  it  expands  and  divides  into  its  terminating  branches ; the  anterior  or  the 


196 


THE  DUBLIN  DISSECTOR, 


radial  nerve  descends  along  the  inner  side  of  the  supinator  longus,  which  it 
supplies,  and  external  to  the  radial  artery;  about  the  middle  of  the  fore-arm 
or  a little  lower,  this  nerve  passes  behind  the  tendon  of  the  supinator  longus, 
and  becoming  cutaneous  descends  behind  the  radius  to  the  back  of  the  hand, 
where  it  divides  into  two  considerable  branches,  one  for  the  integuments  of 
the  thumb,  the  other  expands  on  the  dorsum  of  the  hand  and  supplies  the  in- 
dex and  middle  finger,  and  communicates  with  the  dorsalis  ulnaris  nerve. 
The  deep  branch  of  the  musculo-spiral  nerve  or  the  posterior  inter-osseal 
nerve,  winds  backwards  round  the  upper  part  of  the  radius  and  the  supinator 
brevis,  it  then  descends  along  the  back  part  of  the  fore-arm,  with  the  posterior 
inter-osseal  artery,  and  divides  into  several  branches  superficial  and  deep, 
which  supply  the  two  layers  of  extensor  muscles.  Circumflex  or  articular 
nerve,  arises  from  the  lower  part  of  the  plexus,  descends  round  the  lower  edge 
of  the  sub-scapular  muscle,  and  passing  backwards  and  outwards,  leaves  the 
axilla  by  a large  opening  between  the  humerus  and  the  long  head  of  the  tri- 
ceps, above  the  tendons  of  the  latissimus  dorsi  and  teres  major  muscles,  and 
below  the  capsular  ligament  of  the  shoulder  joint,  it  then  winds  round  the 
neck  of  the  humerus,  attached  to  the  internal  surface  of  the  deltoid  ; in  this 
course  this  nerve  sends  some  small  branches  to  the  sub-scapular  and  the  adja- 
cent muscles,  it  then  divides  into  two  branches,  a superior  and  inferior,  both 
of  which  encircle  the  neck  of  the  humerus,  and  send  their  numerous  subdivi- 
sions into  the  deltoid  muscle. 

The  Dorsal  Nerves  are  twelve  in  number,  the  first  pair  passes  between 
the  first  two  dorsal  vertebra ; and  the  last  pair  below"  the  last  dorsal  vertebra, 
they  also  all  divide  into  the  posterior  and  an  anterior  or  intercostal  branch; 
the  posterior  branches  are  small,  pass  backwards  betw’een  the  traverse  pro- 
cesses, and  supply  the  muscles  and  integuments  of  the  back  and  loins;  of  the 
anterior  branches  that  of  the  1st  dorsal  is  the  largest,  it  rises  above  the  neck 
of  the  first  rib,  and  joins  the  last  cervical  in  the  brachial  plexus ; the  anterior 
branches  of  the  2nd  and  3d  are  smaller,  they  proceed  backwards  and  outwards 
between  the  corresponding  ribs,  and  covered  internally  by  the  pleura;  at  die 
angle  of  each  rib  they  pass  between  the  intercostal  muscles,  run  along  the 
groove  in  the  lower  edge  of  each  rib,  supply  the  surrounding  muscles,  and 
opposite  the  axilla  each  sends  a filament  across  this  cavity  to  the  integuments 
on  the  inner  and  back  part  of  the  arm  ; these  filaments  are  named  the  nerves  of 
Wrisberg,  or  the  cutaneous  nerves  of  the  arm;  these  two  intercostal  or  spi- 
nal nerves  then  continue  on  in  their  course  below  the  first  and  second  ribs, 
and  ultimately  end  in  small  cutaneous  and  muscular  branches,  which  are 
lost  in  the  lateral  and  fore-part  of  the  thorax ; the  anterior  or  intercostal 
branches  of  the  remaining  nine  dorsal  nerves  all  pass  in  a similar  manner  be- 
tween the  ribs,  and  supply  not  only  the  intercostal  but  also  the  adjacent  mus- 
cles; the  last  two  are  chiefly  distributed  to  the  abdominal  muscles  and  to  the 
diaphragm  ; the  twelfdi  dorsal  sends  a branch  close  to  the  vertebrae  to  join  the 
first  lumbar;  all  these  anterior  branches  of  the  dorsal  nerves  opposite  the  neck 
of  each  rib  are  connected  by  one  or  two  short  branches  to  the  ganglions  of  the 
sympathetic. 

Lumbar  Nerves;  of  these  there  are  five  pair,  they  are  larger  than  the  dor- 
sal, like  them  they  divide  into  posterior  and  interior  branches;  the  posterior 
are  distributed  to  the  lumbar  muscles;  the  anterior  branches  unite  with  each 


OR  MANUAL  OF  ANATOMY. 


197 


other  in  the  substance  of  the  psoas  and  form  the  lumbar  plexus ; this  long  and 
somewhat  triangular  plexus  is  situated  along  the  sides  of  the  four  inferior  lum- 
bar vertebras : it  communicates  above  with  the  last  dorsal  and  below  with 
the  first  sacral,  and  divides  into  the  following  branches;  inguino-cutaneous, 
anterior  crural,  obturator  and  lumbo-sacral.  The  inguino-cutaneous  are  gen- 
erally three  in  number ; they  descend  from  the  two.  first  lumbar  nerves,  pass 
though  the  psoas,  and  descend  behind  the  peritonaeum ; the  first  or  the  external 
descends  obliquely  outwards  over  the  quadratuslumborum  muscle  to  the  mid- 
dle of  the  crest  of  the  ilium  it  then  sends  several  branches  to  the  abdominal  mus- 
cles, and  divides  into  a cutaneous  branch  which  passes  to  the  integuments 
on  the  outer  part  of  the  thigh  and  into  the  external  spermatic  nerve  which 
passes  beneath  the  internal  oblique  muscle,  attaches  itself  to  the  spermatic 
cord,  and  distributes  its  branches  to  the  cremaster  muscle  and  to  the  scro- 
tum in  the  male,  or  to  the  round  ligament  and  labium  in  the  female  ; the 
second  or  the  middle,  inguino-cutaneous  descends  internal  to  the  last,  pierces 
the  abdominal  muscles  close  to  the  anterior  superior  spine  of  the  ilium,  and 
is  distributed  to  the  skin  on  the  outer  part  of  the  thigh  ; the  third  or  inter- 
nal inguino-cutaneous  descends  internal  to  the  last,  and  divides  near  Pou- 
part’s  ligament  into  two  branches;  one  accompanies  the  spermatic  ves- 
sels and  is  lost  on  the  cord,  the  other  follows  the  crural  vessels  and  is 
lost  in  the  integuments  and  glands  of  the  groin.  The  anterior  crural  nerve 
arises  in  the  lumbar  plexus  from  the  four  superior  nerves ; it  perforates  the 
psoas,  descends  obliquely  outwards  along  its  external  side,  on  the  iliacus  in- 
ternus,  covered  by  the  iliac  fascia,  and  passes  beneath  Poupart’s  ligament  about 
half  an  inch  external  to  the  femoral  artery ; it  is  then  covered  by  the  fascia 
lata,  becomes  flat  and  broad,  and  divides  into  two  fasciculi,  a superficial  and 
a deep;  the  superficial  separates  into  four  or  five  long  branches  which  pierce 
the  fascia  lata  and  descends  along  the  inner  and  fore-part  of  the  thigh  to  the 
knee,  some  of  these  accompany  the  saphena  vein.  The  deep  fasciculus  is 
largpr,  it  immediately  divides  into  numerous  muscular  branches  which  sup- 
ply the  muscles  on  the  outer  and  fore-part  of  the  thigh ; they  are  divided  into 
the  external  and  internal  branches,  the  former  supply  the  vastus  externus, 
rectus,  iliacus  internus,  and  tensor  vaginae  muscles  ; the  internal  supply  the 
saratorus,  vastus  internus,  and  crurteus  ; three  or  four  accompany  the  femoral 
artery  near  to  the  knee  ; two  or  three  of  these  pass  into  the  adjoining  muscles, 
and  one,  the  internal  saphenus  nerve,  continues  to  descend  to  the  inner  side 
of  the  knee  between  the  tendons  of  the  gracilis  and  sartorius ; it  then  be- 
comes attached  to  the  saphena  vein,  and  twines  round  this  vessel  as  far  as  the 
inner  side  of  the  foot;  in  this  course  it  gives  numerous  filaments  to  the  inte- 
guments of  the  leg. 

The  obturator  nerve  is  smaller  than  the  preceding,  it  arises  chiefly  from 
the  third  lumbar,  it  perforates  the  psoas,  and  descends  obliquely  inwards 
along  the  inner  side  of  that  muscle  to  the  obturator  foramen,  through  the  up- 
per part  of  which  it  escapes  into  the  groin,  where  it  is  covered  by  the  pecti- 
naeus,  and  where  it  divides  into  its  two  branches  an  auterior  and  posterior, 
having  previously  sent  some  twigs  to  the  obturator  internus ; the  anterior 
branch  is  lost  in  the  adductor  brevis,  pectinaeus,  and  vastus  internus,  and 
communicates  with  the  anterior  crural ; the  posterior  branch  supplies  the  gra- 
cilis, the  adductor  magnus  and  longus.  The  lumbo-sacral  nerve  proceeds 


198 


THE  DUBLIN  DISSECTOR, 


from  the  fourth  and  fifth  lumbar  nerves  into  the  pelvis,  and  soon  divides  into 
two  branches,  the  superior  gluteal  and  the  communicating;  the  glutaeal 
escapes  through  the  upper  part  of  the  sciatic  notch,  and  is  distributed  to  the 
gluteus  medius  and  minimus  muscles  along  with  the  branches  of  the  glutaeal 
artery ; the  communicating  branch  joins  the  first  of  the  following  nerves  in 
the  sacral  or  sciatic  plexus. 

The  Sacral  Nerves  are  five  pair,  they  divide  within  the  spinal  canal  into 
their  anterior  and  posterior  branches,  the  latter,  very  small,  pass  through  the 
posterior  sacral  holes  and  supply  the  muscles  and  integuments;  the  anterior 
branches  are  very  large,  particularly  the  three  superior,  the  two  last  are  much 
smaller ; these  five  nerves,  with  the  branch  from  the  last  lumbar,  form  the 
sacral  plexus,  large  and  flat,  placed  on  the  sacrum  and  pyramidal  muscle  be- 
hind the  rectum,  and  the  other  pelvic  viscera,  it  sends  off  the  following 
branches  both  internal  and  external ; the  internal  or  pelvic  are  the  haemorrhoidal 
and  vesical,  and  in  the  female  the  uterine  and  the  vaginal ; the  external 
branches  are  the  inferior  gluteal,  the  inferior  or  lesser  sciatic,  posterior  cuta- 
neous, pudic,  and  great  sciatic  or  posterior  crural.  The  hsemorrhoidal,  vesical, 
uterine  and  vaginal  branches  are  all  small  nerves  which  arise  from  the  upper 
part  of  the  plexus,  are  entangled  with  accompanying  vessels,  and  interlace 
with  each  other;  they  are  distributed  to  the  different  pelvic  viscera,  as  their 
names  imply.  The  lesser  sciatic  nerve  escapes  from  the  pelvis  with  the  former 
and  with  the  sciatic  artery,  it  then  passes  downwards  to  the  space  between 
the  tuber  iscliii  and  trochanter  major,  but  nearer  to  the  former,  round  which 
it  twines,  and  at  its  lower  part  divides  into  two  sets  of  branches,  a superficial 
and  a deep;  the  former  pass  over  the  hamstring  muscles  with  the  posterior 
cutaneous  nerve  and  are  lost  in  these  muscles;  and  the  latter  pass  under 
the  muscles,  and  are  distributed  to  the  quadratus  femoris,  upper  part  of  the  ad- 
ductor magnus  muscles  &c.  and  some  go  to  the  hip  joint,  The  inferior  glu- 
teeal  nerve  leaves  the  pelvis  below  the  pyriform  muscle,  and  divides  at  once 
into  several  branches,  which  are  principally  distributed  to  the  gluteus  maxi- 
mus,  some  also  pass  to  the  perinEeum  and  to  the  inner  side  of  the  thigh.  The 
posterior  cutaneous  nerve  arises  in  common  with  the  preceding  from  the 
second  and  third  sacral  nerves,  escapes  from  the  pelvis  below  the  pyriform 
muscle,  becomes  cutaneous,  and  descends  along  the  back  part  of  the  thigh 
and  leg,  and  communicates  with  the  cutaneous  nerves  in  the  latter  region. 
The  pudic  nerve  arises  from  the  third  and  fourth  sacral,  passes  through  the 
great  sciatic  notch  internal  to  the  preceding ; it  then  re-enters  the  pelvis  by  the 
lesser  sciatic  notch,  and  passing  upwards  and  forwards  along  the  internal  sur- 
face of  the  tuber  ischi  towards  the  pubis,  it  divides  into  two  branches,  an 
inferior  and  superior;  the  inferior  ascends  obliquely  forwards  and  inwards 
along  the  ramus  of  the  ischium  to  the  perinaeum,  and  is  distributed  to  the 
muscles  and  integuments  in  that  region,  also  to  the  scrotum  ; the  superior  branch 
continues  its  course  along  the  ramus  of  the  pubis  nearly  to  the  symphysis,  it 
then  passes  forwards  along  the  dorsum  of  the  penis,  increases  in  size  as  it 
approaches  the  glans  penis,  in  the  subcutaneous  cellular  tissue  of  which  it 
terminates ; in  the  female  the  inferior  branch  of  the  pudic  nerve  supplies  the 
labium,  the  superior,  the.  clitoris. 

The  great  sciatic  or  posterior  crural  nerve  is  the  principal  branch  of  the 
sacral  plexus,  and  the  largest  nerve  in  the  body;  it  proceeds  from  the  four 


OR  MANUAL  OF  ANATOMY. 


199 


superior  sacral  nerves,  escapes  from  the  pelvis  below  the  pyriform  muscle, 
sometimes  through  it,  it  then  descends  along  the  back  of  the  thigh  over  the 
gemini,  quadratus,  and  adductor  magnus  as  far  as  the  ham,  where  it  divides 
into  the  external  and  internal  popliteal  nerves ; in  this  course  this  nerve  is 
covered  superiorly  by  the  glutasus  maximus  and  the  hamstrings,  interiorly  by 
the  fascia  lata  and  the  integuments;  the  sciatic  nerve  sends  off  several  cuta- 
neous and  muscular  branches,  the  latter  supply  the  hamstrings,  the  gracilis, 
and  the  adductor  magnus.  The  external  popliteal  or  the  peronxl  nerve  de- 
scends obliquely  outwards  along  with  the  biceps  tendon  to  the  external  con- 
dyle of  the  femur,  it  then  turns  forwards  through  the  peronaeus  longus,  round 
the  neck  of  the  fibula,  and  divides  into  two  branches,  the  musculo-cutaneous 
and  anterior  tibial ; the  peronaeal  nerve,  before  it  arrives  at  the  head  of  the 
fibula,  sends  off  two  or  three  long  branches,  termed  the  external  cutaneous 
nerves  of  the  leg;  these  descend  along  the  outer  and  back  part  of  the  leg, 
and  communicate  with  the  external  saphenus  nerve  a branch  of  the  posterior 
tibial.  The  musculo-cutaneous  nerve  descends  between  the  peronteus  longus 
and  extensor  digitorum  longus;  to  these  and  to  the  short  peronsei  muscles  it 
t sends  several  muscular  branches;  about  the  middle  of  the  leg,  it  perforates 
the  fascia,  and  a little  above  the  outer  malleolus  it  divides  into  the  internal 
and  external  tarsal  nerves  or  dorsal  nerves  of  the  foot;  the  internal  is  distri- 
buted to  the  integuments  of  the  first  and  second  toes,  and  communicates  with 
the  internal  saphenus  nerve  and  with  the  anterior  tibial ; the  external  supplies 
the  integuments  on  the  three  outer  toes,  and  communicates  with  the  internal 
branch  and  with  the  external  saphenus  nerve.  The  anterior  tibial  nerve 
descends  obliquely  forwards  along  with  the  anterior  tibial  artery  between  the 
tibialis  anticus  and  the  extensor  digitorum  longus  and  extensor  pollicis,  which 
muscles  it  supplies;  it  also  sends  branches  through  the  fascia  to  the  integu- 
ments ; it  then  passes  beneath  the  annular  ligament  of  the  tarsus,  and  runs  to 
the  inter-osseous  muscle  between  the  first  two  metatarsal  bones ; on  the  foot  it 
sends  a large  branch  to  the  extensor  digitorum  brevis,  also  several  cutaneous 
and  communicating  filaments,  and  it  terminates  by  supplying  the  first  inter- 
osseal muscle  and  the  integuments  of  the  two  internal  toes  ; in  the  first  inter- 
osseal space  a small  branch  communicates  with  the  plantar  nerves.  The 
internal  popliteal  or  posterior  tibial  nerve  is  larger  than  the  preceding ; it 
descends  nearly  vertically  between  the  heads  of  the  gastrocnemius  and 
solaeus  muscles,  and  behind  the  articulation  of  the  knee  and  the  poplitaeus 
muscle;  it  then  descends  obliquely  inwards  beneath  the  solaeus  and  on  the 
tibialis  posticus  and  flexor  digitorum  longus,  to  the  arch  beneath  the  heel  and 
the  internal  ankle;  it  here  divides  into  the  internal  and  external  plantar 
nerves.  In  the  ham  a quantity  of  fat  separates  this  nerve  from  the  popliteal 
vessels;  below  the  knee  it  becomes  more  closely  connected  to  them,  lying 
superficial  and  a little  to  their  inner  or  tibial  side;  at  the  lower  edge  of  the 
poplitaeus  it  passes  to  the  outer  or  fibular  side  of  the  posterior  tibial  artery 
and  descends  in  that  relation  to  this  vessel  as  far  as  the  internal  malleolar 
region.  The  posterior  tibial  nerve  above  the  knee  gives  off  a small  nerve,  the 
posterior  or  external  saphenus ; this  descends  along  the  back  of  the  leg,  at 
first  covered  by  the  fascia,  afterwards  it  is  subcutaneous  ; it  communicates 
superiorly  with  filaments  from  the  cutaneous  branch  of  the  sciatic  plexus  and 
with  the  external  cutaneous  branches  of  the  peronaeal  nerve;  about  the 


200 


THE  DUBLIN  DISSECTOR, 


middle  of  the  leg  it  is  increased  in  size,  and  accompanies  the  external  saphena 
vein  to  the  external  malleolus,  behind  which  it  passes  ; it  then  curves  forwards 
along  the  outer  edge  of  the  foot,  communicating  with  the  external  dorsal 
nerves  of  the  foot  and  supplying  the  integuments  and  muscles  on  the  outer 
side  of  this  region.  In  the  ham,  the  posterior  tibial  nerve  gives  off  several 
very  large  muscular  branches  to  the  gastrocnemius,  solaeus,  and  plantaris ; 
and  in  its  course  down  the  leg  several  smaller  branches  to  the  deep-seated 
muscles;  it  also  sends  numerous  filaments  around  the  artery;  some  very 
small  twigs  pass  through  the  inter-osseous  space  along  with  the  anterior  tibial 
artery  and  join  the  anterior  tibial  nerve.  The  internal  plantar  nerve  is  larger 
than  the  external ; it  passes  forwards  along  the  inner  side  of  the  tarsus  above 
the  abductor  pollicis,  sends  many  branches  to  the  plantar  muscles  and  to  the 
integuments,  and  arriving  near  the  base  of  the  great  toe,  divides  into  four 
digital  branches  ; the  first  runs  along  the  tibial  side  of  the  first  toe : the  second 
subdivides  and  supplies  the  opposed  sides  of  the  first  and  second  toes;  the 
third,  in  like  manner,  the  second  and  third  toes ; and  the  fourth  the  opposed 
sides  of  the  third  and  fourth  toes  : these  digital  nerves  also  supply  the  lum- 
bricales,  and  communicate  with  the  dorsal  nerves  of  the  foot.  The  external 
plantar  nerve  passes  forwards  and  outwards  above  the  flexor  brevis  to  the 
fifth  metatarsal  bone,  and  divides  into  two  branches;  one,  the  superficial, 
supplies  the  little  toe  and  the  outer  side  of  the  fourth  ; the  deep  branch 
passes  obliquely  inwards  across  the  metatarsus,  and  supplies  the  inter-ossei 
and  the  other  deep  plantar  muscles. 

§ 3. — Dissection  of  the  Ganglions. 

In  addition  to  the  small  ganglions  already  noticed  in  the  description  of  the 
cerebral  nerves,  viz.  the  lenticular  or  opthalmic,  the  spheno-palatine,  or 
Meckel’s,  and  the  sub- maxillary,  also  the  several  ganglions  on  the  spinal 
nerves,  we  find  one  continued  chain  of  these  bodies  placed  anterior  to  the 
vertebral  column  on  either  side  of  the  median  line ; these  ganglions,  on  each 
side,  are  all  connected  to  each  other,  and  resemble  a knotted  cord  ; this  cord 
receives  the  name  of  the  sympathetic  nerve. 

The  Sympathetic  Nerves,  therefore,  are  two  in  number ; they  descend 
from  the  base  of  the  cranium  perpendicularly  along  the  neck,  placed  on  the 
rectus  capitis  and  longus  colli  muscles,  and  behind  the  great  vessels  and 
nerves ; at  the  upper  part  of  the  chest  each  of  these  nerves  is  divided  by  the 
subclavian  artery  into  several  branches,  which  encircle  that  vessel  and  unite 
below  it  in  the  thorax;  through  this  cavity  they  descend  at  first  obliquely 
backwards  and  outwards  along  the  heads  of  the  ribs  and  covered  by  the 
pleura;  they  then  incline  a little  forwards  and  pass  behind  the  true  liga- 
mentum  arcuatum  into  the  abdomen ; through  this  region  they  descend  ob- 
liquely outwards  on  the  fore-part  of  the  lumbar  vertebrae  and  between  the 
psoas  and  the  crus  of  the  diaphragm  ; they  then  sink  into  the  pelvis,  keeping 
close  to  the  sacrum,  and  descend  along  the  anterior  surface  of  this  bone 
obliquely  inwards  : near  its  inferior  extremity,  or  on  the  first  part  of  the 
coccyx,  these  nerves  unite  and  terminate  in  a small  ganglion  named  ganglion 
impar.  The  superior  extremity  of  each  sympathetic  nerve  is  connected  by 
several  filaments  to  several  of  the  cerebral  nerves;  some  of  these  connections 


OR  MANUAL  OF  ANATOMY. 


201 


have  been  improperly  termed  the  origin  of  the  sympathetic ; in  their  course 
along  the  spinal  column  each  nerve  regularly  communicates  with  every  pair 
of  the  spinal  nerves,  with  each  of  the  cervical  nerves  by  one  filament,  and 
with  each  of  the  dorsal,  lumbar,  and  sacral  nerves  by  two ; the  sympathetic 
nerves  may  either  be  considered  as  independent  parts  of  the  nervous  system 
communicating  by  numerous  branches  with  every  portion  of  that  system,  or 
they  may  each  be  regarded  as  a nervous  cord  formed  by  the  union  of  branches 
from  all  the  spinal  and  from  several  of  the  cerebral  nerves  ; the  latter  is  pro- 
bably the  more  correct  view.  The  sympathetic  nerves  send  off  numerous 
branches,  which  are  chiefly  destined  to  supply  the  heart  and  the  coats  of  the 
great  vessels  and  all  the  pelvic  and  abdominal  viscera  except  the  stomach  ; 
these  branches  arise  from  the  ganglions  on  these  nerves ; of  these  there  are 
generally  three  in  the  neck ; in  the  back  and  loins  they  correspond  with  the 
number  of  vertebrae  in  those  regions,  and  in  the  pelvis  there  are  three  on  each 
side  and  the  coccygeal  or  impar  ganglion  below ; these  ganglions  and  their 
branches  must  be  next  examined. 

Th e.  cervical  ganglions  are  three,  the  superior,  middle,  and  inferior;  the 
superior  cervical  ganglion  is  of  an  oval  figure  and  reddish  color,  extending 
from  the  first  to  the  third  cervical  vertebra,  placed  on  the  rectus  capitis  anticus, 
behind  the  carotid  artery  and  jugular  vein,  and  internal  to  the  eighth  and 
ninth  cerebral  nerves:  this  ganglion  sends  off  several  branches,  viz.  superior, 
inferior,  internal,  external,  and  anterior ; the  superior  branches  are  two  in 
number;  they  ascend  in  the  carotid  canal  to  the  cavernous  sinus,  and  commu- 
nicate with  the  sixth,  and  with  the  vidian  branch  of  the  fifth ; in  this  situation 
a plexus  and  sometimes  a ganglion  may  be  observed  on  the  external  surface 
of  the  artery,  fine  soft  reddish  filaments  pass  from  this  to  the  several  nerves 
which  are  about  to  enter  the  orbit  through  the  foramen  lacerum,  also  to  the 
gasserian  ganglion  of  the  fifth,  and  several  continue  attached  to  the  carotid 
artery,  and  are  lost  in  its  cerebral  branches.  The  inferior  or  descending 
branches  of  the  superior  ganglion  are  small  filaments  to  join  the  laryngeal 
nerves  and  the  vagus,  the  superior  cardiac  nerve,  (to  be  described  presently,) 
and  the  continued  cord  of  the  sympathetic  itself.  The  internal  branches 
unite  with  the  pharyngeal  plexus;  the  external  join  the  superior  cervical 
nerves,  and  the  anterior  unite  with  branches  of  the  vagus  and  facial,  and  form 
a plexus  around  the  carotid  artery  ; from  this  several  branches  extend  along 
the  external  carotid,  and  form  plexuses  around  each  of  its  principal  branches, 
which  are  named  accordingly.  The  middle  cervical  ganglion  is  sometimes 
wanting ; it  is  smaller  than  the  superior,  of  a triangular,  often  an  irregular 
form,  is  situated  behind  the  carotid  near  the  curve  of  the  inferior  thyroid 
artery,  opposite  the  fifth  vertebra,  and  upon  the  longus  colli  muscle  ; it  sends 
off  branches  in  different  directions  which  communicate  with  the  cervical  nerves 
and  with  the  vagus  ; it  also  sends  some  filaments  to  join  the  cardiac  nerves. 
The  inferior  cervical  ganglion  is  of  an  irregular  figure;  it  frequentlv  appears 
to  consist  of  several  small  ganglions  connected  to  each  other  by  reddish  fila- 
ments ; it  is  situated  between  the  transverse  process  of  the  last  cervical 
vertebra  and  the  neck  of  the  first  rib,  behind  and  on  either  side  of  the  vertebral 
artery,  and  between  the  scalenus  and  longus  colli  muscles;  filaments  from  it 
communicate  with  the  phrenic  nerve  and  with  the  brachial  plexus;  several 
also  encircle  the  subclavian  artery  and  extend  along  that  trunk  and  its  several 
26 


202 


THE  DUBLIN  DISSECTOR, 


branches,  particularly  along  the  vertebral  artery ; from  it  also  the  inferior 
cardiac  nerves  proceed.  The  student  may  next  examine  the  cardaic  nerves  ; 
there  are  three  on  each  side,  they  are  named  superior,  middle,  and  inferior ; 
the  superior  cardiac  nerve,  though  very  small,  takes  a long  course;  it  arises 
by  two  or  three  filaments  from  the  superior  cervical  ganglion,  descends  along 
the  side  of  the  trachea  behind  the  carotid  artery  to  the  chest;  in  this  course, 
it  communicates  with  the  laryngeal  nerves,  with  the  vagus,  and  with  the  in- 
ferior and  middle  ganglions  of  the  sympathetic;  there  is  sometimes  a small 
ganglion  upon  it  near  the  inferior  thyroid  artery;  at  the  lower  part  of  the 
neck  it  passes  behind  the  subclavian  vein  and  over  the  arteria  innominata ; it 
here  divides  into  several  filaments ; some  pass  along  the  coats  of  that  vessel 
to  the  aorta,  others  join  the  recurrent  nerve  and  the  middle  and  inferior  car- 
diac nerves  ; the  superior  cardiac  nerve  on  the  left  side  has  a similar  origin 
and  course  in  the  neck,  but  it  enters  the  chest  in  a deeper  situation  than  the 
nerve  of  the  right  side;  it  descends  between  the  left  carotid  and  subclavian 
arteries,  and  arriving  at  the  arch  of  the  aorta,  divides  into  branches,  some  of 
which  pass  behind  that  vessel  and  join  the  cardiac  ganglion;  others  unite  with 
the  cardiac  nerves  from  the  sympathetic,  or  from  the  vagus  and  recurrent. 
The  middle  cardiac  nerve  on  the  right  side  is  generally  the  largest  of  the  car- 
diac nerves;  on  the  left  side  it  is  sometimes  wanting,  the  inferior  in  such  a 
case  will  be  of  a greater  size  ; it  arises  by  several  filaments  from  the  middle 
cervical  ganglion  or  from  the  sympathetic  nerve  about  the  middle  of  the  neck; 
it  descends  either  a single  cord,  or  divided  into  several  parallel  filaments 
behind  and  internal  to  the  carotid,  and  enters  the  thorax  anterior  to  the  sub- 
clavian artery  ; it  here  is  joined  by  large  branches  from  the  vagus  and  recur- 
rent nerves,  it  then  descends  obliquely  inwards  along  the  side  of  the  arteria 
innominata,  glides  between  the  arch  of  the  aorta  and  the  division  of  the 
trachea,  and  terminates  in  the  cardiac  ganglion  or  plexus.  On  the  left  side 
the  middle  cardiac  nerve  sometimes  arises  front  the  inferior  cervical  ganglion  ; 
it  enters  the  chest  along  the  subclavian  artery,  and  either  joins  the  inferior 
cardiac  nerve  or  enters  the  cardiac  plexus.  The  inferior  cardiac  nerve  or 
nerves  proceed  from  the  inferior  cervical  ganglion,  and  on  the  right  side 
descend  along  the  arteria  innominata  to  the  arch  of  the  aorta,  round  which 
they  pass  to  its  fore-part,  and  terminate  principally  in  the  anterior  cardiac 
plexus  ; some  branches  pass  between  the  aorta  and  pulmonary  artery  to  the 
cardiac  ganglion;  these  inferior  cardiac  nerves  communicate  with  the  pre- 
ceding, and  with  the  vagus  and  its  recurrent;  they  form  an  irregular  network 
or  plexus  in  their  course  to  the  aorta;  on  the  left  side  these  nerves  accompany 
the  subclavian  artery  and  partly  join  the  middle  cardiac  nerve,  and  partly 
the  cardiac  plexus.  The  cardiac  plexus  or  cardiac  ganglion  is  situated 
behind  the  ascending  aorta  near  its  origin,  and  in  front  of  the  trachea  and  of 
the  right  pulmonary  artery ; of  a grayish  color  and  irregular  form,  it  consists 
of  a plexus  of  nerves  formed  by  the  cardiac  nerves  from  opposite  sides,  also 
by  branches  of  the  eighth  pair  and  the  recurrent  nerves ; in  the  meshes  of 
this  plexus  several  small  ganglions  are  enclosed,  and  to  the  aggregate  of  these 
the  term  cardiac  ganglion  is  applied ; superiorly  it  receives  the  middle  cardiac 
nerves  from  each  side,  also  some  filaments  from  the  superior  cardiac,  particu- 
larly on  the  left  side,  and  also  some  from  the  inferior  cardiac,  particularly  on 
the  right  side ; the  greater  portion  of  the  I'ight  superior  cardiac  joins  the  middle 


OR  MANUAL  OF  ANATOMY. 


203 


cardiac  before  toe  latter  arrives  at  the  plexus,  and  the  inferior  is  chiefly  dis- 
tributed on  the  fore-part  of  the  aorta  to  the  anterior  cardiac  plexus  : from  the 
great  cardiac  plexus  branches  proceed  in  various  directions,  some  pass  back- 
wards encircling  the  posterior  coronary  artery,  and  forming  a plexus  around 
it,  and  accompanying  its  branches  into  the  substance  of  the  heart,  others  pass 
forwards  round  the  aorta,  form  the  anterior  cardiac  plexus  on  it  and  on  the 
right  pulmonary  artery,  and  vena  cava  ; from  this  plexus  branches  descend 
over  the  right  auricle,  accompanying  the  anterior  coronary  artery,  and  form 
plexuses  around  it  and  its  several  branches;  from  this  ganglion  also  numerous 
nerves  descend  on  either  side  along  the  pulmonary  vessels  and  communicate 
with  the  pulmonary  plexus ; on  the  left  side  these  branches  encircle  the 
ductus  anteriosus. 

The  sympathetic  nerves  in  the  thorax  have  twelve  ganglions  on  each  side, 
sometimes  only  eleven,  the  last  cervical  and  first  dorsal  being  then  united ; 
each  of  the  thoracic  ganglions  is  small  and  triangular,  the  base  towards  the 
spine,  the  apex  externally;  covered  by  the  pleura  and  placed  on  the  heads  of 
the  ribs,  the  first  ganglion  is  the  largest;  they  all  communicate  by  one  or  two 
branches,  which  ascend  obliquely  outwards,  with  the  anterior  or  intercostal 
branch  of  the  spinal  nerves ; from  the  base  or  anterior  edge  of  each  ganglion 
small  branches  pass  forwards  to  the  mediastinum,  ramify  on  the  aorta  and 
adjacent  vessels,  and  communicate  with  the  pulmonary  plexus.  From  the  six 
inferior  ganglions  the  splanchnic  nerves  arise ; these  are  two  in  number  on 
each  side,  the  greater  and  lesser  or  superior  and  inferior.  The  great  splanchnic 
nerve  arises  by  distinct  roots  from  the  sixth,  seventh,  eighth,  ninth,  and  tenth 
ganglions,  these  descend  obliquely  forwards  and  unite  on  the  tenth  dorsal 
vertebra  into  one  cord,  which  enters  the  abdomen  either  along  with  the  aorta 
or  separated  from  it  by  a fasciculus  of  the  diaphragm ; each  nerve  then  expands 
into  the  semilunar  ganglion.  The  lesser  splanchnic  nerve  arises  by  two  roots 
from  the  tenth  and  eleventh  ganglions ; these  unite  on  the  side  of  the  last 
dorsal  vertebra ; this  small  nerve  then  enters  the  abdomen  through  the  crus 
of  the  diaphragm,  communicates  with  the  preceding,  and  ends  in  the  renal 
plexus.  In  the  abdomen  we  find  the  semilunar  and  the  lumbar  ganglions  of 
each  side;  the  semilunar  ganglion  of  each  side  is  situated  on  the  diaphragm, 
and  partly  on  the  aorta  on  either  side  of  the  coeliac  axis,  and  above  and  behind 
the  supra-renal  capsule ; these  are  the  largest  ganglions  on  the  sympathetic  ; 
they  communicate  with  each  other  by  several  filaments  on  which  small  gan- 
glions are  placed ; this  communication  surrounds  the  coeliac  axis,  and  is  termed 
the  solar  plexus ; this  plexus  is  situated  behind  the  stomach,  in  front  of  the 
aorta  and  above  the  pancreas ; from  it  numerous  nerves  pass  off  in  various 
directions ; these  nerves  accompany  the  blood  vessels,  and  form  plexuses 
around  each,  which  are  named  according  to  their  destination,  hepatic,  splenic, 
and  gastric ; these  plexuses  communicate  with  the  eighth  pair ; from  the  solar 
plexus  branches  descend  in  front  of  the  aorta  ; these  subdivide  at  the  renal 
and  mesenteric  arteries,  accompany  these  vessels,  form  plexuses  around  each, 
which  are  named  accordingly  the  renal,  superior,  and  inferior  mesenteric 
plexuses,  into  each  of  these,  branches  from  the  lumbar  ganglions  enter.  The 
lesser  splanchnic  nerve  enters  the  renal  plexus  ; from  each  renal  plexus  de- 
scends the  spermatic  plexus,  which  in  the  male  descends  in  the  spermatic 
cord  and  supplies  the  testicle  ; in  the  female  it  enters  the  pelvis  and  supplies 


204 


THE  DUBLIN  DISSECTOR, 


the  ovarium  and  uterus.  From  the  inferior  mesenteric  plexus  branches  de- 
scend to  the  edge  of  the  pelvis,  unite  with  others  from  the  lumbar  ganglions, 
and  form  a plexus  around  the  internal  iliac  artery  and  its  pelvic  branches  ; 
this  is  termed  the  hypogastric  plexus  : it  is  joined  by  numerous  filaments  from 
the  lumbar  and  sacral  ganglions  of  the  sympathetic,  and  it  communicates  with 
the  pelvic  branches  of  the  sacral  plexus.  The  lumbar  ganglions  of  the  sym- 
pathetic are  five  on  each  side,  sometimes  only  four  or  three  ; they  are  situated 
on  the  anterior  and  lateral  parts  of  the  bodies  of  the  vertebrae  internal  to  the 
psoas,  of  an  oval  figure,  smaller  than  the  cervical ; each  ganglion  is  connected 
by  one  or  two  communicating  branches  which  pass  through  the  psoas  to  the 
anterior  branches  of  the  lumbar  spinal  nerves ; from  the  fore-part  of  each 
several  filaments  pass  in  front  of  the  aorta  and  assist  in  the  formation  of  the 
different  abdominal  plexuses  which  are  principally  derived  from  the  solar 
plexus.  The  sacral  ganglions  are  three  or  four  in  number ; the  first  is  oval, 
the  remaining  are  of  an  irregular  form  ; they  each  communicate  with  the  sacral 
nerves  and  send  filaments  to  the  hypogastric  and  pelvic  plexuses ; from  the 
last  ganglion  on  each  side  a small  branch  passes  inwards  in  front  of  the  coccyx; 
these  branches  unite  in  the  middle  line  and  form  a small  plexus,  sometimes  a 
distinct  ganglion  is  placed  here  ; from  the  convexity  of  the  arch  which  these 
branches  form,  filaments  oass  off  to  the  coccygseus,  levator,  and  sphincter 
ani  muscles. 


CHAPTER.  IV. 

ORGANS  OF  SENSE. 

Under  this  head  may  be  placed  the  anatomy  of  the  nose,  or  the  organ  of 
smell ; the  tongue,  or  the  organ  of  taste ; the  eye,  or  the  organ  of  vision  : and 
the  ear  or  the  organ  of  hearing ; to  these  may  be  added  the  integuments  or  the 
organ  of  touch. 

§ 1. — Anatomy  of  the  Nose . 

Several  bones  enter  into  the  formation  of  this  organ ; these  are  all  lined  by 
a highly  sensible  mucous  membrane;  to  the  anterior  part  of  the  bones  of  the 
nose,  the  cartilages,  which  form  the  septum  and  alse  nasi,  are  attached.  The 
nose  is  bounded  superiorly  by  the  nasal,  frontal,  ethmoid  and  sphenoid  bones, 
the  roof  of  the  nose  is  arched,  and  has  different  aspects,  the  anterior  part  looks 
downwards  and  backwards,  the  middle  perpendicularly  downwards,  and  the 
posterior  part  downwards  and  forwards ; inferiorly  by  the  palatine  plates  of 
the  maxillary  and  palate  bones,  the  floor  of  the  nose  is  nearly  horizontal,  but 
with  a slight  inclination  backwards,  and  is  concave  in  the  transverse  direction, 
on  either  side  by  the  superior  maxillary,  unguis,  spongy,  etnmoid  and  palate 
bones,  and  by  the  internal  pterygoid  plates ; it  is  divided  into  two  symmetrical 
portions  (the  nares)  by  the  septum,  which  is  composed  of  the  azygos  plate  of 
the  sphenoid,  the  nasal  lamella  of  the  ethmoid,  the  vomer,  the  spines  of  the 
palate  and  maxillary  bones,  and  by  a cartilage ; the  external  wall  of  each  naris 


OR  MANUAL  OF  ANATOMY. 


205 


is  deeply  groved  by  three  fossae  or  meatuses,  the  superior,  middle,  and  inferior; 
they  are  situated  between  the  spongy  bones,  the  middle  is  the  widest ; the 
nasal  or  lachrymal  duct  opens  into  the  anterior  third  of  the  inferior  meatus, 
the  Eustachian  tube  behind,  but  on  a level  with  the  inferior  spongy  bone,  and 
at  the  side  of  the  septum  anteriorly  may  be  observed  the  superior  orifice  of  the 
anterior  palatine  canal,  which,  although  a distinct  opening  superiorly  towards 
the  cavity  of  the  nose,  yet  inferiorly  towards  the  mouth,  forms  with  the  one  of 
the  opposite  side  a common  foramen ; this  communication,  however,  between 
the  nose  and  mouth  does  not  exist  in  the  recent  state  in  the  human  subject, 
but  does  so  in  some  animals,  and  in  these  Jacobson  has  ascribed  a peculiar 
office  to  it;  into  the  middle  meatus,  the  antrum  maxillare  opens  by  a small 
oblique  slit,  which  looks  backwards  and  inwards,  and  although  in  the  dry  bone 
appears  tolerably  large,  yet  in  the  recent  state  admits  only  a small  probe,  on 
account  of  the  mucous  membrane  being  thrown  into  a small  fold  which  sur- 
rounds it,  and  in  front  of  this,  a groove,  named  the  infundibulum,  which  leads 
from  the  frontal  sinus  ; into  this  groove  the  anterior  ethmoid  cells  open ; into 
the  upper  meatus,  the  posterior  ethmoid  cells  and  the  sphenoid  sinus  open ; 
each  naris  opens  posteriorly  into  the  pharynx,  above  the  velum,  by  an  oblong 
oval  opening ; these  are  separated  from  each  other  by  the  vomer,  the  internal 
pterygoid  plates  bound  them  externally,  the  sphenoid  above  and  the  palate 
bones  below.  To  the  anterior  edge  of  each  naris  the  cartilages  composing  the 
alse  nasi  are  attached,  these  are  five  in  number,  one  in  the  centre, two  at  each 
side ; the  central  cartilage  is  triangular  and  vertical,  attached  superiorly  and 
posteriorly  to  the  bony  septum,  its  anterior  edge  is  thick  and  sub-cutaneous, 
and  attached  on  either  side  to  the  lateral  cartilages ; the  lateral  cartilages  are 
two,  one  superior  and  triangular,  attached  to  bone,  the  other  inferior,  and 
irregularly  curved,  convex  externally,  and  attached  to  the  preceding  and  to  the 
septum;  in  the  alae  nasi  small  pieces  of  cartilage  also  may  be  noticed  distinct 
from  the  larger  cartilages.  All  the  internal  surface  of  the  nose  and  of  the 
sinuses  communicating  with  it,  are  lined  by  a soft,  vascular,  and  highly  sen- 
sible mucous  membrane;  this  is  the  pituitary  or  Schneiderian  membrane  ; this 
mucous  membrane  is  continuous  anteriorly  with  the  integuments ; it  adheres  to 
all  the  internal  surface  of  the  bones  of  the  nose,  lines  the  sinuses,  is  continuous 
through  the  nasal  duct  with  the  membrana  conjunctiva  of  each  orbit;  round 
the  lower  extremity  of  each  duct  it  forms  a slight  circular  fold  ; and  poste- 
riorly it  is  continuous  with  the  membrane  of  the  pharynx  and  Eustachian 
tubes ; this  membrane  adheres  inseparably  to  the  periosteum ; it  is  villous, 
very  vascular,  soft  and  thick  on  the  septum  and  turbinated  bones;  at  the 
extremities  of  the  latter  it  forms  thick  fleshy-looking  folds  or  lips;  in  the  sinuses 
it  is  pale  and  thin ; it  is  constantly  moistened  with  a mucous  secretion ; 
mucous  glands  are  not  distinct  in  it;  the  olfactory  or  first  pair  of  nerves  are 
distributed  to  it  in  the  form  of  numerous  plexuses,  it  is  also  supplied  with 
branches  from  the  opthalmic  and  superior  maxillary  divisions  of  the  5th  pair ; 
the  first  pair  are  generally  believed  to  endow  the  membrane  with  the  peculiar 
sensibility  of  smelling;  Magendie,  however,  has  recently  made  some  experi- 
ments to  prove  that  the  branches^of  the  5th  pair  are  accessory  to  this  func- 
tion. 


206 


THE  DUBLIN  DISSECTOR, 


§ 2. — Organ  of  Taste. 

The  organ  of  taste  resides  in  the  mucous  membrane  of  the  tongue ; this  mem- 
brane is  spread  over  the  muscular  substance  of  the  tongue,  adheres  closely  to  it, 
and  presents  a number  of  projections  or  papillae  ; the  tongue  is  very  vascular  and 
is  supplied  with  six  nerves ; the  gustatory  is  distributed  anteriorly  and  chiefly 
to  the  papillae,  the  lingual  to  the  inferior  surface  and  to  its  muscular  substance 
the  glosso-pharnygeal  to  the  muscular  substance  and  mucous  membrane  at  its 
base ; experiments  have  proved  that  the  5th  nerve  endows  this  organ  with  its 
peculiar  sense,  that  of  taste;  and  that  the  lingual  or  9th  is  its  motor  nerve; 
the  glosso-pharyngeal  is  probably  for  the  purpose  of  connecting  the  tongue 
in  sympathy  with  the  stomach  and  the  respiratory  organs ; the  form  of  the 
tongue  has  been  already  described,  (see  page  22.) 

§ 3. — Anatomy  of  the  Ear. 

The  parts  composing  this  complicated  organ  may  be  divided  into  three 
classes;  the  1st  concludes  the  external  ear,  or  the  cartilages  and  meatus  ex  - 
ternus;  the  2d  the  tympanum  with  the  Eustachian  tube,  ossicula  auditus  and 
mastoid  cells;  the  3d  the  labyrinth  or  internal  ear,  which  includes  the  vestibule, 
semicircular  canals,  cochlea,  and  meatus  internus  with  the  portio  mollis. 

The  external  ear  consists  of  the  pinna  or  auricle  and  the  meatus  externus  ; 
the  pinna  is  composed  of  a thin  fibro-cartilaginous  plate,  curved  in  different 
directions,  so  as  to  present  different  eminences  and  depressions ; the  convex 
edge  which  forms  the  outline  of  it  is  the  helix,  below  this  is  a short  semicir- 
cular fold,  the  anti-helix , this  divides  superiorly  into  two  crura ; the  depression 
between  these  is  the  fossa  navicularis ; in  front  of  the  meatus  is  an  eminence, 
the  tragus,  directed  backwards  over  the  meatus  ; opposite  to  this  is  a slight 
projection,  the  anti-tragus ; within  these  several  eminences  is  a deep  conical 
cavity,  the  concha  which  leads  to  the  meatus  externus,  below  this,  is  the  pen- 
dulous fold  of  the  integuments,  or  the  lobe  of  the  ear ; these  several  eminences 
are  supposed  to  be  of  use  in  protecting  the  internal  parts,  also  in  collecting 
and  directing  the  sound  towards  the  matus ; in  some  subjects  pale  muscular 
fibres  may  be  found  on  these  eminences,  they  have  been  named  according  to 
their  situation,  as  distinct  muscles,  tragicus,  anti -tragi cus,  major  and  minor 
helicis,  and  transversalis  auris;  these  fibres  may  have  some  power  in  approxi- 
mating these  cartilages,  and  thus  deepening  the  concha,  they  are  seldom 
marked  in  the  human  subject,  but  in  the  lower  classes  of  animals  they  are 
strong  and  distinct.  The  meatus  auditorius  externus  extends  from  the 
concha  to  the  membrana  tympani,  first  forwards,  upwards,  and  inwards,  then 
downwards  and  inwards;  it  is  therefore  curved,  or  concave  downwards,  about 
an  inch  in  length, one  half  cartilaginous, the  other  osseous;  it  is  lined  by  skin, 
beneath  which  are  a number  of  ceruminous  glands,  the  cuticle  is  continued 
over  the  membrana  tympani,  from  which  it  readily  separates,  and  is  furnished 
with  a number  of  fine  hairs,  which  are  longer  and  more  obvious  externally. 

The  middle  ear  consists  of  the  tympanum  and  its  appendages.  The  mem- 
brane tympani  separates  this  cavity  from  the  meatus  externus,  the  latter  must 
be  cut  vertically  to  expose  this  membrane;  it  is  placed  obliquely,  its  lower 


OR  MANUAL  OF  ANATOMY. 


207 

edge  being  more  internal  than  the  upper,  or  nearer  the  median  line,  it  there- 
fore looks  downwards,  outwards,  and  forwards  ; it  is  concave  towards  the 
meatus,  convex  towards  the  tympanum,  being  drawn  in  the  latter  direction  by 
its  connection  to  the  handle  of  the  malleus ; it  consists  of  three  layers,  an 
external  or  cuticular,  an  internal  or  mucous,  and  a middle  or  fibrous,  which  is 
dry  and  elastic.  The  cavity  of  the  tympanum  may  be  seen  either  by  dividing 
the  membrane  just  described,  or,  without  injuring  the  latter,  the  roof  of  the 
cavity  may  be  broken  or  cut  through  at  the  lower  and  internal  part  of  the 
squamous  plate  ; this  cavity  is  placed  between  the  meatus  externus  and  the 
labyrinth;  it  is  of  an  irregular  figure,  rather  circular ; it  presents  on  its  internal 
side  a tubercular  eminence,  named  th epromontory,  and  two  foramina,  one  above, 
the  other  below  that  eminence ; the  superior  foramen  or  fenestra  ovalis,  is  closed 
by  a membrane,  to  which  the  base  of  the  stapes  bone  is  attached,  this  opening 
communicates  with  the  vestibule  ; the  inferior  or  the  foramen  rotundum  is  also 
closed  by  a membrane,  it  communicates  with  the  internal  part  of  the  cochlea 
or  the  scala  tympani ; the  posterior  wall  of  the  tympanum  presents  superiorly 
the  opening  of  a short  canal,  which  leads  to  the  mastoid  cells,  these  are  of 
irregular  form  and  differ  in  different  subjects;  beneath  this  is  the  pyramid,  a 
small  bony  projection,  hollow,  containing  the  muscle  of  the  stapes  ; beneath 
the  pyramid  is  the  small  foramen  leading  from  the  aqueduct  of  Fallopius,  and 
transmitting  the  corda  tympani.  The  tympanum  presents  anteriorly  the  open- 
ings of  two  canals,  one  superior  containing  the  tensor  tympani  muscle,  the 
other,  the  inferior,  is  the  Eustachian  tube ; this  descends  obliquely  forwards 
and  inwards,  and  terminates  by  a trumpet-shaped  mouth,  behind  the  posterior 
nares,  on  a level  with  the  inferior  spongy  bone;  this  canal  is  small, and  osseous 
posteriorly,  anteriorily  it  is  large  and  formed  of  membrane  externally,  and  of 
a curved  fibro-cartilage  internally;  it  is  lined  by  mucous  membrane,  which  is 
prolonged  from  the  pharynx  into  the  tympanum  ; through  this  tube  the  atmos- 
phere can  pass  from  the  fauces  into  the  tympanum,  to  support  the  latter  on 
its  internal  surface.  In  the  superior  boundary  of  the  tympanum  are  some 
small  foramina  for  the  passage  of  blood-vessels  ; its  inferior  boundary  presents 
the  glenoid  fissure,  through  which  pass  the  corda  tympani,  the  tendon  of  the 
laxator  tympani,  and  the  processus  gracilis  of  the  malleus.  Within  the  cavity 
of  the  tympanum  are  four  small  bones,  first  the  malleus,  attached  to  the  mem- 
brana  tympani,  and  resting  on  the  second,  the  incus,  one  leg  of  which  is  con- 
nected to  the  third,  the  orbicular,  which  is  articular  to  the  fourth,  the  stapes, 
which  rests  on  the  membrane  of  the  fenestra  ovalis,  between  which  and  the 
membrana  tympani  these  four  bones  form  a connecting  chain,  for  the  purpose 
of  conveying  the  impression  of  sound  from  the  membrana  tympani  to  the  inter- 
nal ear.  The  malleus  is  immediately  behind  the  membrana  tympani,  it  pre- 
sents a head,  neck,  handle,  a long  and  short  process ; the  head  is  smooth  and 
articulated  behind  with  the  incus,  the  neck  is  small,  and  gives  origin  anteriorly 
to  the  processus  gracilis,  which  is  about  half  an  inch  long,  traverses  the  glenoid 
fissure,  and  gives  attachment  to  the  tendon  of  the  laxator  tympani  muscle ; 
the  handle  descends  from  the  neck,  adheres  to  the  membrana  tympani,  and 
has  a short  process  superiorly  for  the  insertion  of  the  tensor  tympani  muscle. 
The  incus  is  internal  and  posterior  to  the  malleus,  presents  a body,  and  a long 
and  short  crus ; the  body  is  directed  forwards  and  upwards,  and  receives  the 
head  of  the  malleus,  the  superior  crus  is  short,  and  lies  in  the  foramen  of  the 


208 


THE  DUBLIN  DISSECTOR, 


mastoid  cells,  the  inferior  long,  and  perpendicular,  is  articulated  with  the  fol- 
lowing • The  os  orbiculare,  extremely  small,  is  between  the  incus  and  the 
following:  The  stapes  is  placed  horizontally,  the  base  is  on  the  fenestra 
ovalis,  the  head  is  articulated  to  the  orbicular  bone,  the  neck  gives  attachment 
to  the  stapedius  muscle,  the  crura  of  the  stirrup  are  separated  by  a space  filled 
by  membrane. 

There  are  three  muscles  in  the  tympanum,  viz.  stapedius,  tensor,  and  lax- 
ator  tympani.  Stapedius  arises  within  the  pyramid ; its  tendon  is  inserted  into 
the  neck  of  the  stapes ; its  use  is  to  raise  the  stapes,  and  to  press  its  base 
against  the  fenestra  ovalis.  Tensor  tympani  arises  in  the  canal  in  the  petrous 
bone  above  the  Eustachian  tube,  passes  backwards  into  the  tympanum,  and  is 
inserted  into  the  short  process  below  the  neck  of  the  malleus ; use  to  draw  the 
malleus  into  the  tympanum,  and  thus  to  increase  the  concavity  of  the  mem- 
brana  tympani.  Laxator  tympani  arises  from  the  spinous  process  of  the 
sphenoid  bone,  and  from  the  Eustachian  tube,  ends  in  a delicate  tendon  which 
passes  through  the  glenoid  fissure  along  with  the  cordi  tympani,  and  is  in- 
serted into  the  processus  gracilis  of  the  malleus  or  the  process  of  Raw.  Use, 
to  draw  the  malleus  forwards,  and  thus  to  relax  the  membrana  tympani. 

The  labrynth , or  the  internal  ear,  consists  of  the  vestibulum,  cochlea,  semi- 
circular canals,  and  meatus  interims.  Vestibulum  is  a small  elliptical  cavity 
behind  the  cochlea  and  in  front  of  the  semicircular  canals,  the  fenestra  ovalis 
opens  on  its  external  side,  the  five  orifices  of  the  semicircular  canals  open  supe- 
riorly and  posteriorly,  one  opening  from  the  cochlea  is  anteriorly,  and  poste- 
riorly is  the  orifice  of  a small  canal  called  the  aqueduct  of  the  vestibule.  A 
delicate  but  vascular  membrane  lines  this  cavity ; it  is  filled  by  a peculiar  fluid, 
and  extends  into  the  aqueduct  of  the  vestibule.  The  semicircular  canals  are 
three  in  number,  superior,  posterior,  and  horizontal ; the  two  first  are  vertical ; 
they  are  surrounded  by  the  petrous  bone  in  front  of  the  mastoid  cells  and  be- 
hind the  vestibule ; the  superior  and  posterior  are  joined  by  one  end ; there  are, 
therefore,  but  five  orifices  of  these  canals  in  the  vestibule  ; each  of  these  tubes 
is  lined  by  a vascular  membrane  filled  with  a fluid  which  communicates  with 
that  in  the  vestibule.  The  cochlea  is  in  the  anterior  part  of  the  petrous  bone, 
it  is  somewhat  conical,  the  base  towards  the  meatus  internus,  the  apex  towards 
the  carrtid  artery  ; the  cochlea,  internally,  consists  of  a central  pillar  placed 
somewhat  horizontally,  named  the  modiolus,  and  of  a spiral  tube  passing  round 
this  axis  two  turns  and  a half ; this  tube  is  divided  into  two  by  a thin  osseous 
and  membranous  plate,  called  lamina  spiralis,  and  the  two  tubes  are  the  scalae 
of  the  cochlea ; near  the  apex  of  the  cochlea  these  scalas  communicate  ; near  the 
base  they  separate;  one,  the  scala  vestibuli,  communicates  with  the  vestibule  ; 
the  other,  the  scala  tympani,  with  the  tympanum  through  the  fenestra  rotunda ; 
the  modiolus  is  hollow  and  expanded  towards  the  apex ; this  expansion  is  called 
the  infundibulum ; a branch  of  the  auditory  nerve  passes  through  this  cavity  ; 
the  aqueduct  of  the  cochlea  terminates  in  a small  slit-like  opening  in  the 
petrous  bone  just  below  the  meatus  auditorius  internus.  The  portio  mollis  of 
the  seventh  pair  of  nerves  descends  along  the  meatus  auditorius  internus, 
divides  into  several  fine  branches  which  are  distributed  to  the  membrane 
lining  the  vestibule,  cochlea,  and  semicircular  canals. 


OR  MANUAL  OF  ANATOMY. 


209 


§ 4. — Anatomy  of  the  Eye. 

Under  this  head  we  shall  examine  not  only  the  globe  of  the  eye  but  its  appen- 
dages; these  are  the  eye-lids,  the  lachrymal  apparatus,  and  the  muscles  of  the 
orbit. 

The  muscles  of  the  orbit  are  seven  in  number,  viz.  the  levator  palpebrse 
superioris,  the  obliquus  superior  and  inferior,  and  the  four  recti ; to  obtain  a 
satisfactory  view  of  these  muscles,  the  roof  and  a considerable  portion  of  the 
external  side  of  the  orbit  must  be  removed  ; then  the  periosteum  having  been 
divided,  the  first  muscle  appears. 

Levator  Palpebrje  Superioris  is  the  highest  muscle  in  the  orbit ; it  arises 
narrow  and  tendinous  from  the  upper  edge  of  the  foramen  opticum,  passes 
forwards  and  outwards  beneath  the  frontal  nerve,  and  becoming  broader,  bends 
down  in  front  of  the  eye  ; it  then  ends  in  a dense  cellular  expansion  which  is 
inserted  into  the  superior  border  of  the  tarsal  cartilage  and  into  the  superior 
palpebral  sinus  of  the  conjunctiva  behind  the  palpebral  ligament.  Use,  to  ele- 
vate and  retract  into  the  orbit  the  upper  eye-lid. 

OBLiquus  Superior,  at  the  upper  and  inner  part  of  the  orbit,  arises  on  the 
inner  side  of  the  preceding,  passes  forwards  along  the  os  planum,  ends  in  a 
round  tendon  which  plays  through  the  fibro-cartilaginous  pulley  which  is 
attached  to  the  inner  angle  of  the  os  frontis ; this  tendon  is  then  reflected  back- 
wards, outwards,  and  downwards,  between  the  superior  rectus  and  the  eye,  and 
then  becoming  broad  and  thin,  is  inserted  into  the  sclerotic  coat  between  the 
superior  and  external  recti,  about  midway  beween  the  entrance  of  the  nerve 
and  the  insertion  of  the  superior  rectus.  Use,  to  draw  the  eye  forwards  and 
inwards,  also  to  rotate  it,  so  as  to  direct  the  cornea  downwards  and  inwards 
towards  the  tip  of  the  nose.  Some  authors  consider  it  a rotator  outwards. 

OsLiquus  Inferior  is  situated  at  the  inferior  and  anterior  part  of  the  orbit"; 
it  arises  tendinous  from  the  orbital  edge  of  the  superior  maxillary  bone  above 
the  infra-orbital  foramen,  and  external  to  the  lachrymal  sac;  it  ascends 
obliquely  outwards  and  backwards  below  the  inferior  rectus,  and  is  inserted 
by  a tendinous  expansion  into  the  sclerotic  coat  behind  the  transverse  axis 
of  the  eye,  and  between  the  sclerotic  coat  and  the  external  rectus.  Use, 
to  draw  the  globe  forwards  and  inwards,  and  to  rotate  it  upwards  and  out- 
wards. 

Recti  muscles  are  four  in  number,  the  superior  is  called  attollens  ocv.li,  the 
inferior  depressor  oculi,  the  internal  adductor,  and  the  external  abductor  oculi ; 
they  all  arise  around  the  optic  foramen ; the  external  has  an  additional  attach- 
ment to  the  foramen  lacerum ; they  all  pass  forwards  around  the  optic  nerve, 
separated  from  it  by  the  ciliary  vessels  and  nerves,  and  by  a great  quantity 
of  fat ; a little  beyond  the  middle  of  the  eye  they  become  tendinous,  and  are 
each  inserted  about  a quarter  of  an  inch  behind  the  cornea ; the  four  tendons 
are  connected  together  by  an  aponeurosis  which  is  attached  to  the  conjunctiva ; 
the  use  of  these  muscles  is,  collectively,  to  retract  the  eye  into  the  orbit,  and 
individually  to  move  it,  as  their  names  imply. 

Under  the  head  of  lachrymal  apparatus  we  may  consider  the  lachrymal 
gland,  membrana  conjunctiva,  palpebrse,  and  lachrymal  passages.  The  lach- 
rymal gland  is  placed  in  the  upper  part  of  the  orbit,  behind  the  external 
27 


210 


THE  DUBLIN  DISSECTOR, 


angular  process  of  the  os  frontis,  above  the  external  rectus  and  the  conjunc- 
tiva; of  a flattened  oval  figure,  and  a pale  color,  separable  into  two  or  more 
lobes,  which,  like  other  conglomerate  glands,  can  be  separated  into  numerous 
granules;  these  are  united  by  a loose  capsule  ; from  these,  five  or  six  small 
ducts  proceed  and  open  behind  the  upper  eye-lid  along  the  line  of  reflection 
of  the  conjunctiva  from  the  palpebra  to  the  sclerotic. 

The  membrana  conjunctiva  is  a mucous  membrane  lining  each  palpebra, 
and  continuous  at  their  margin  with  the  integuments;  it  also  covers  the  an- 
terior part  of  the  globe  ; near  the  inner  canthus  it  is  thrown  into  a semilunar 
fold,  and  is  continued  through  the  puncta  lachrymalia  into  the  nasal  sac  and 
duct,  and  becomes  continuous  with  the  mucous  membrane  of  the  nose.  This 
membrane  is  more  vascular  on  the  palpebrse  and  caruncula  than  on  the  sur- 
face of  the  eye:  it  is  loosely  connected  to  the  sclerotic  coat  to  within  half 
an  inch  of  the  cornea  ; it  then  becomes  so  delicate  and  so  adherent  that  it  is 
difficult  to  separate  it  further,  and  although  it  is  generally  described  as  being 
continued  over  the  cornea,  it  is  impossible  to  dissect  it  from  it  unless  pre- 
viously macerated  or  changed  by  disease ; at  the  inner  canthus  of  the  orbit  it 
is  thrown  forwards  by  a fleshy  looking  tubercle  of  a conical  figure,  the  carun- 
cula lachrymalis ; this  is  composed  of  a few  mucous  follicles  and  the  bulbs 
of  some  fine  hairs  that  project  from  its  surface.  The  conjunctiva  is  a secre- 
ting, and  according  to  some,  an  absorbing  surface;  it  is  constantly  moistened 
by  the  fluid  it  secretes,  and  occasionally  by  the  lachrymal  secretion  ; it  serves, 
as  its  name  implies,  to  join  the.  eye-lids  to  the  eye,  to  facilitate  the  motions 
of  the  former,  and  thereby  to  clear  the  surface  of  the  latter;  it  also  closes 
the  orbit  against  any  extraneous  substance,  and  serves  to  support  and  confine 
the  eye-ball  in  its  several  motions. 

Palpebral  are  composed  of  the  skin,  the  orbicular  muscle,  a thin  cartilage 
connected  to  the  base  of  the  orbit  by  a cellulo-ligamentous  connection,  and 
lined  by  conjunctiva ; in  the  superior  there  is  also  the  expansion  of  the  leva- 
tor pal  pebrae  muscle;  the  upper  is  larger  than  the  lower  eye-lid,  therefore 
when  they  are  closed  the  former  descends  below  the  transverse  axis  of  the 
eye,  and  the  inferior  ascends  but  little  to  meet  it;  they  are  both  concave  pos- 
teriorly, adapted  to  the  surface  of  the  eye,  their  margins  are  thick,  and  fur- 
nished anteriorly  with  the  eye-lashes,  posteriorly  with  numerous  mucous 
follicles;  their  opposed  edges  are  sloped  off  obliquely  towards  the  eye,  so 
that  when  the  lids  are  closed  a sort  of  triangular  canal  is  formed,  the  base  of 
which  is  the  surface  of  the  eye ; along  this  canal  the  tears  are  supposed  by 
some  to  be  directed  inwards  towards  the  puncta,  others  however  deny  that 
any  such  space  can  exist,  and  affirm  that  the  lachrymal  secretion  flows  along 
each  palpebral  sinus,  and  is  directed  inwards  by  the  action  of  the  orbicular 
muscle ; the  skin  of  each  palpebra  is  thin,  the  sub-cutaneous  cellular  tissue 
very  loose  and  reticular ; beneath  this  the  orbicular  muscle  is  expanded. — 
(See  page  3.)  The  tarsal  cartilages  are  thin  elastic  plates;  the  superior  is 
semilunar  and  larger  than  the  inferior,  which  is  long  and  narrow;  the  ciliary 
margins  are  thick;  their  orbital  edges  thin  and  connected  to  the  orbit  by  the 
palpebral  ligaments  which  are  a continuation  of  the  periosteum  ; these  liga- 
ments are  stronger  towards  the  temple,  where  they  decussate  and  attach  the 
cartilages  at  their  external  canthus  or  commissure  ; the  tendo  oculi  fixes  them 
internally.  Between  each  tarsal  cartilage  and  the  conjunctiva  are  the  Meibomian 


OR  MANUAL  OF  ANATOMY. 


211 


gland  or  follicles ; they  are  of  a white  or  yellow  color,  are  arranged  in 
nearly  parallel  vertical  rows,  and  are  more  numerous  in  the  upper  eye-lid  ; 
they  secrete  a thin  sebaceous  fluid,  which  is  discharged  by  a row  of  small 
holes  along  the  edge  of  each  tarsus  behind  the  ciliee.  The  cilise  arises  from 
bulbs  which  are  beneath  the  skin ; those  of  the  upper  eye-lid  are  more 
numerous  than  those  in  the  lower ; both  are  curved,  convex  towards  each, 
other. 

The  Puncta  Lachrymalia  are  two  small  holes  always  open,  directed  back- 
wards and  outwards,  opposite  each  other;  they  meet  when  the  lids  are  closed; 
each  is  situated  in  a little  cartilaginous  projection,  about  two  lines  from  the 
inner  canthus ; each  is  the  orifice  of  a small  duct. 

The  Lachrymal  ducts  extend  from  the  puncta  to  the  lachrymal  sac;  the 
superior  is  longer  and  more  curved  than  the  inferior;  the  former  is  concave 
interiorly  ; the  latter  is  nearly  straight,  a little  concave  upwards  ; they  both 
open  into  the  external  part  of  the  sac,  a little  above  its  middle,  sometimes  by 
one,  and  sometimes  by  distinct  orifices,  behind  the  tendo  oculi ; each  duct  is 
surrounded  by  a process  of  that  tendon,  and  lined  by  mucous  membrane. 

The  Lachrymal  sac  is  a small  oval  pouch  of  mucous  membrane,  closed 
above  and  leading  below  into  the  nasal  duct,  it  is  situated  in  a fossa  formed 
by  the  maxillary  and  unguis  bones,  covered  by  the  integuments,  the  tendon 
and  some  fleshy  fibres  of  the  orbicularis  muscle,  also  by  a strong  fascia  which 
is  derived  from  that  tendon  and  connected  to  the  surrounding  bony  margin. 
A small  muscle  has  been  described  by  Mr.  Horner  as  arising  from  the  edge 
of  the  os  unguis,  and  inserted  into  the  lachrymal  sac  and  ducts  ; he  conceives 
it  to  have  the  power  of  compressing  the  sac,  and  directing  the  ducts  and  their 
contents  towards  it;  it  is  not  however  in  ail  subjects  to  be  distinguished  from 
the  orbicular,  which  last  can  effect  the  purpose  ascribed  to  this  small  muscle. 

The  Nasal  Duct  (about  three-fourths  of  an  inch  in  length  in  the  recent 
state)  descends  from  the  sac  obliquely  backwards  and  a little  outwards  sur- 
rounded by  the  maxillary,  unguis,  and  inferior  spongy  bones ; beneath  the 
latter  it  opens  by  a small  slit-like  orifice,  which  is  surrounded  by  a circular 
fold  of  mucous  membrane,  into  the  lower  meatus,  about  an  inch  from  the  an- 
terior part  of  the  naris  ; this  duct  is  formed  of  mucous  membrane  only,  it  is 
connected  to  the  periosteum.  The  nerves  and  vessels  of  the  orbit  have  been 
already  examined.  The  nerves  of  the  palpebrse  are  derived  from  the  portio 
dura  of  the  7th,  from  the  lachrymal,  frontal,  and  nasal  branches  of  the  opthal- 
mic,  and  from  the  infra-orbital  branches  of  the  5th  pair  of  nerves ; the  vessels 
are  branches  of  the  opthalmic,  temporal,  and  facial. 

DISSECTION  OF  THE  GLOBE  OF  THE  EYE. 

It  will  facilitate  the  student  in  learning  the  anatomy  of  the  eye,  to  dissect 
this  organ  in  some  of  the  inferior  animals  ; almost  every  part  of  importance  may 
be  examined  with  equal  advantage  in  the  eye  of  the  sheep,  ox,  or  pig,  as  in 
that  of  the  human  subject ; many  of  the  minute  parts  are  even  on  a larger 
scale,  and  can  be  dissected  with  greater  ease  : we  also  have  it  in  our  power 
in  general  to  dissect  the  eyes  of  the  inferior  animals  in  a perfectly  fresh 
state. 

The  eye  is  situated  at  the  anterior  and  internal  part  of  the  orbit,  behind  the 


212 


THE  DUBLIN  DISSECTOR, 


conjunctiva,  surrounded  bj  muscles  and  fat,  and  connected  posteriorly  by  the 
optic  nerve  ; the  axes  of  the  eyes  are  parallel  to  each  other,  therefore  not  so 
to  those  of  the  orbits  ; each  eye  is  nearly  spherical ; the  antero-posterior  axis, 
which  is  nearly  an  inch,  being  about  one  or  two  lines  greater  than  the  trans- 
verse or  vertical  axis;  the  cornea,  which  is  a segment  of  a smaller  sphere,  and 
which  forms  about  the  anterior  fifth  of  the  globe,  being  superadded  to  the 
larger  sphere,  formed  by  the  sclerotic;  this  spherical  form  favors  the  motion 
of  the  eye-ball.  The  eye  is  composed  of  fluids  or  humors  enclosed  in  differ- 
ent tunics  ; the  latter  are  the  sclerotic,  choroid  and  retina;  the  first  is  a 
fibrous,  the  second  a vascular,  and  the  third  a nervous  coat ; the  humors  are 
the  aqueous  crystaline  and  vitreous;  these  are  also  enclosed  in  distinct 
capsules. 

Tunica  Sclerotica  is  a dense,  opaque,  fibrous  membrane,  extending  from 
the  optic  nerve  to  the  cornea  ; the  nerve  perforates  it  about  a line  internal  to 
its  centre  by  a small  conical  aperture,  which  appears  traversed  by  fibres,  so 
as  to  present  a cribriform  appearance;  it  is  doubtful  however,  whether  this 
indistinct  appearance  may  not  partly  depend  on  the  central  vein  and  artery 
of  the  retina  which  accompany  the  nerve  through  this  opening ; the  sheath  of 
the  optic  nerve  is  continuous  with  the  fibres  of  this  membrane  ; the  external 
surface  is  rough  and  perforated  by  several  holes ; anteriorly  it  receives  the 
cornea,  and  is  so  intimately  connected  to  it,  that  maceration  alone  can  sepa- 
rate them ; both  are  sloped  off  obliquely  as  well  as  slightly  grooved ; the 
sclerotic  overlaps  the  cornea;  their  connection  is  still  further  secured  by  the 
conjunctiva  externally,  and  by  the  membrane  of  the  aqueous  humor  internally ; 
a vertical  section  of  this  tunic  from  behind  forwards  will  show  its  great  thick- 
ness near  the  optic  nerve,  and  its  thinness  in  the  centre  ; anteriorly  it  is  again 
strengthened  by  the  tendinous  expansion  of  the  recti  muscles;  this  expansion 
has  been  improperly  called  the  tunica  albuginea ; the  sclerotic  consists  of 
fibres  which  run  in  every  direction,  but  which  do  not  form  distinct  laminae  ; 
its  internal  surface  is  smooth  and  glistening ; the  ciliary  vessels  and  nerves 
run  between  it  and  the  choroid  ; from  this  surface  a fine  serous-like  lamina* 
may  be  raised  ; this  is  reflected  on  the  choroid  coat. 

The  Cornea  forms  the  anterior  fifth  of  the  eye ; it  is  nearly  circular,  its 
transverse  diameter  being  a little  greater  than  its  vertical ; it  is  very  smooth 
and  transparent,  of  a laminated,  not  a fibrous  texture  ; some  fine  cellular  tis- 
sue connects  the  laminae  to  each  other;  the  cornea  is  more  thick  and  pulpy  in 
the  child  than  in  the  adult ; it  is  covered  anteriorly  by  a fine  and  closely 
adhering  membrane,  which  though  generally  considered  a continuation  of  the 
conjunctiva,  is  very  different  from  it  in  its  structure  and  properties ; the  con- 
cave surface  of  the  cornea  is  lined  by  a fine  elastic  membrane,  which  is 
described  by  some  as  a part  of  the  membrane  of  the  aqueous  humor ; it  is, 
however,  a membrane  sui  generis ; it  is  best  seen  in  the  eye  of  a horse,  which 
has  been  macerated  for  some  days,  the  external  laminae,  which  are  now  opaque, 
can  be  peeled  off,  leaving  behind  it  this  elastic  cornea,  which  preserves  its 
proper  curve  and  transparency,  if  it  be  cut  it  will  curl  upon  itself,  thus  ex- 
hibiting true  elastic  cartilaginous  properties.  Fix  the  eye  in  a small  shallow 
ve.^^l,  which  can  be  immersed  occasionally  under  water,  carefully  raise  a 


continuation  of  the  tunica  arachnoidea,  which  accompanies  the  optic  nerve 


OR  MANUAL  OF  ANATOMY. 


213 


small  portion  of  the  sclerotic,  pass  in  some  air  between  it  and  the  choroid, 
these  membranes  can  thus  be  easily  separated;  then  dissect  off  the  sclerotic, 
this  tunic  can  be  readily  detached  as  far  as  the  cornea,  here  it  adheres  to  the 
ciliary  ligament;  this  connection  maybe  separated  with  the  handle  of  the 
knife,  the  cornea,  or  one  half  of  it,  may  also  be  removed  with  the  sclerotic  and 
the  next  tunic  of  the  eye  will  be  exposed,  the  choroid,  with  its  appendages, 
the  ciliary  ligament,  ciliary  processes,  and  iris. 

The  Choroid  coat  extends  from  the  optic  nerve  all  round  the  eye,  between 
the  sclerotic  and  retina,  as  far  as  the  ciliary  ligament,  where  it  appears  on  the 
external  surface  to  terminate,  but  when  a portion  of  it  is  raised,  its  internal 
surface  will  be  found  to  extend  inwards,  in  the  form  of  folds  or  processes, 
termed  ciliary,  to  be  examined  presently;  the  external  surface  of  the  choroid 
is  smooth,  and  loosely  connected  to  the  sclerotic  by  the  ciliary  vessels  and 
nerves,  and  by  fine  cellular  tissue ; this  surface  is  generally  tinged  by  the 
pigment  which  transudes  through  it;  on  this  layer  of  the  choriod,  numerous 
fine  vascular  ramifications,  running  in  parallel  arches,  may  be  observed ; these 
are  connected  chiefly  with  the  veins,  and  are  termed  the  Yasa  vorticosa;  raise 
a portion  of  the  choroid,  by  tearing  it  from  the  retina  with  a forceps  ; its  in- 
ternal surface  is  covered  by  a brown  pigment,  which  is  thicker  before  than 
behind,  for  a small  distance  round  the  optic  nerve  it  is  deficient ; wash  off  this 
pigment,  the  choroid  will  be  found,  if  previously  injected,  to  be  very  vascular 
and  villous;  this,  the  internal  layer,  which  by  dissection  can  be  separated 
from  the  external,  is  termed  membrana  Ruyschiana  ; the  ciliary  arteries  sup- 
ply this  coat  with  blood,  for  the  purpose  of  secreting  the  pigment,  which  has 
the  effect  of  absorbing  all  rays  of  light  which  strike  the  sides  of  the  retina; 
the  optic  nerve  passes  through  a round  opening  in  this  membrane,  the  edges  of 
which  are  not  connected  to  the  nerve  ; this  tunic  is  more  dense  anteriorly  than 
posteriorly. 

The  Ciliary  Ligament  corresponds  to  the  junction  of  the  iris  to  the  choroid, 
and  of  the  cornea  to  the  sclerotic ; it  forms  a ring  of  gray  color,  about  two 
lines  broad,  of  a soft  and  cellular  texture,  and  has  some  resemblance  to  a 
ganglion. 

The  Ciliary  Processes  are  sixty  or  seventy  small  triangular  folds  of  the 
choroid  coat,  which  are  arranged  in  a radiated  manner  around  the  lens  on  the 
fore-part  of  the  vitreous  humor,  each  extends  inwards  and  backwards  from  the 
ciliary  ligament  as  far  as  the  border  of  the  lens ; each  of  these  processes,  as 
well  as  the  interstices  between  them,  are  covered  by  the  pigmentum  nigrum, 
the  term  corona  ciliaris  is  applied  to  this  part ; the  anterior  edge  of  each  pro- 
cess is  connected  to  the  ciliary  ligament  and  iris,  the  posterior  to  the  vitreous 
humor,  and  the  internal  is  loose,  and  forms  the  circumference  of  the  posterior 
chamber  of  the  eye. 

The  Iris  is  a delicate  circular  membrane,  floating  in  the  aqueous  humor 
and  suspended  vertically  behind  the  cornea,  so  as  to  divide  the  space  between 
this  and  the  lens  into  two  chambers,  an  anterior  and  a posterior,  the  former  is 
the  larger  of  the  two  ; these  chambers  communicate  through  the  central  aper- 
ture in  the  iris,  the  Pupil:  tins  aperture  is  a little  nearer  its  nasal  than  its 
temporal  side;  the  external  border  of  the  iris  is  fixed  to  the  ciliary  ligament, 
its  posterior  surface  is  also  in  part  attached  to  the  same  and  to  the  ciliary  pro- 
cesses ; this  surface  is  covered  by  pigment,  and  is  named  uvea ; the  anterior 


214 


THE  DUBLIN  DISSECTOR, 


surface  is  covered  by  the  fine  membrane  of  the  aqueous  humor,  and  streaked 
with  different  colored  lines,  some  of  which  take  a radiated  course  from  the 
circumference  towards  the  pupil,  near  which  they  cross,  divide,  and  unite 
again,  and  appear  to  form  or  to  end  in  a fasciculus  of  circular  fibres,  which 
bound  the  pupil,  and  which  are  of  a darker  tint.  The  iris,  when  examined 
with  a magnifying  glass,  has  a villous  appearance  ; when  the  pigment  is 
washed  off  the  posterior  surface,  the  fibrous  structure  is  evident  there  also, 
and  bristles  may  even  be  passed  beneath  some  of  the  fasciculi ; the  iris  is 
supplied  with  numerous  arteries  and  nerves ; the  former  are  branches  of  the 
long  and  anterior  ciliary,  the  latter  are  derived  from  the  lenticular  ganglion, 
and  from  the  nasal  nerve  ; it  is  not  generally  agreed  on  whether  the  fibrous 
appearance  of  the  iris  depends  on  the  peculiar  arrangement  of  its- vessels  and 
nerves,  or  whether  it  possesses  a true  muscular  structure ; its  functions  may 
lead  one  to  incline  to  the  latter  opinion,  as  the  pupil  has  the  power  of  contract- 
ing rapidly  when  a strong  light  approaches  the  eye,  and  of  again  dilating  when 
the  light  is  weak  ; the  use,  therefore,  of  the  iris  is  to  regulate  the  quantity  of 
light  which  is  to  enter  the  eye.  The  pupil  is  closed  in  the  foetus  by  a delicate 
but  vascular  membrane,  the  membrana  pupillaris  ; this  membrane  is  ruptured 
either  at,  or  a short  time  previous  to  birth. 

The  Retina  may  be  best  exposed  by  gently  tearing  off  the  choroid  (the  eye 
being  held  under  water),  and  then  placing  an  inverted  glass  globe  filled  with 
clear  diluted  spirits  over  the  dissection,  the  retina  will  become  slightly  opaque, 
and  have  a magnified  appearance.  The  optic  nerve  having  pierced  the  cho- 
roid coat  ends  in  this  thin  and  delicate  membrane,  which  is  transparent  in  the 
very  recent  eye,  but  soon  becomes  opaque  after  death;  the  retina  extends 
around  the  sides  and  fore-part  of  the  vitreous  humor  without  adhering  to  it, 
as  far  forwards  as  within  two  lines  of  the  lens  ; here  the  nervous  matter  ends 
by  an  abrupt  line,  along  which  a small  blood  vessel  runs.  The  retina  is  divi- 
sible into  three  layers:  first,  lamina  serosa;  second,  lamina  nervosa;  and 
third,  lamina  vasculosa.  The  external  or  serous  layer  is  extremely  delicate, 
it  may  be  separated  by  gentle  pressure  with  the  handle  of  the  knife,  under 
water.  This  membrane  was  discovered  by  Dr.  Jacob.  The  middle,  or  the 
nervous  layer,  is  soft  and  gray,  and  continuous  with  the  optic  nerve ; the 
internal  or  vascular  layer  is  very  delicate ; it  lies  on  the  vitreous  humor,  and  is 
continued  on  its  fore-part  to  the  capsule  of  the  lens,  where  it  becomes  adhe- 
rent to  the  hyaloid  membrane.  Dissect  off  the  posterior  half  of  the  retina 
from  the  vitreous  humor,  or  cut  transversely  a fresh  eye,  and  allow  the 
humors  to  fall  out,  then  look  on  the  concave  surface  of  the  retina,  and  we  may 
observe  in  the  centre  of  the  optic  nerve  a small  dark  point,  thejoorns  opticus  ; 
this  is  the  central  artery  of  the  retina,  which  then  spreads  its  branches  in  the 
internal  layer  of  the  retina;  about  two  lines  external  to  this,  and  in  the  axis 
of  the  eye,  is  a small  yellow  or  orange  spot,  th epunctum  aureum;  the  retina 
is  thrown  into  folds  around  this ; some  describe  a perforation  and  deficiency 
of  the  retina  at  this  spot,  it  rather  appeal's,  however,  to  depend  on  some  pecu- 
liar organization.  The  humors  of  the  eye  are  the  aqueous,  crystaline,  and 
vitreous. 

The  aqueous  humor  is  perfectly  colorless,  about  five  grains  in  quantity : it 
fills  the  anterior  and  posterior  chambers,  the  former  about  two  lines,  the  latter 
about  half  a line  in  depth.  This  fluid  is  supposed  to  be  secreted  by  a fine 


OR  MANUAL  OF  ANATOMY. 


215 


membrane,  which  is  continued  from  the  cornea  over  the  iris,  and  through  its 
pupillary  margin  to  its  posterior  surface ; in  the  human  eye,  however,  it  is 
impossible  to  trace  any  such  membrane  through  this  extent.  This  fluid  sup- 
ports the  cornea  and  the  iris,  the  latter  can  float  and  move  freely  in  a fluid 
of  such  thin  consistence. 

The  crystaline  humor  is  a transparent  double  convex  lens,  a little  more 
prominent  behind  than  before,  imbedded  in  the  fore-part  of  the  vitreous 
humor  behind  the  anterior  third  of  the  eye,  and  a little  nearer  to  its  nasal  than 
its  temporal  side.  Its  axis  corresponds  to  that  of  the  pupil  ; it  is  surrounded 
by  a fine  capsule,  which  is  thin  and  soft  posteriorly,  but  anteriorly  dense,  and 
peculiarly  elastic ; a small  quantity  of  fluid  (liquor  Morgagni)  is  contained 
between  the  lens  and  its  capsule  ; the  lens  is  retained  in  its  place  by  the  hya- 
loid membrane,  which  splits  into  two  laminae  at  its  border ; these  laminae  pass, 
one  before,  the  other  behind  it,  and  become  connected  to  the  proper  capsule; 
a small  triangular  canal  (canal  of  Petit)  is  enclosed  between  these  layers,  the 
base,  is  formed  by  the  circumference  of  the  lens.  This  canal  is  intersected 
by  fine  septa,  it  therefore  presents  a cellular  or  vesicular  appearance  when 
distended  by  air  or  injection.  Some  describe  this  canal  as  formed  by  the 
division  of  the  lamina  vasculosa  into  two  layers.  The  lens  is  soft  and  pulpy 
externally,  more  dense  towards  the  centre,  or  a little  internal  to  that  point; 
maceration  or  boiling  causes  it  to  separate  into  wedge  or  triangular  shaped 
pieces,  the  apices  towards  the  centre : each  piece  appears  composed  of  suc- 
cessive plates,  and  each  plate  has  a fibrous  structure.  In  the  foetus  the  lens 
is  reddish  and  very  soft ; in  the  adult  it  is  transparent,  and  in  the  old  it  has 
an  amber  or  yellowish  cast  towards  the  centre  : the  capsule  of  the  crystaline 
lens  receives  some  fine  vessels  from  the  central  artery  of  the  retina.  The 
lens  refracts  the  rays  of  light,  and  causes  them  to  converge  to  a focus  on  the 
retina. 

The  vitreous  humor  fills  the  two  posterior  thirds  of  the  globe  of  the  eye, 
it  is  thin  and  almost  watery,  but  being  enclosed  in  a fine  membrane,  it  has  a 
gelatinous  consistence;  this  membrane  is  called  hyaloid,  it  encloses  the  fluid, 
and  sends  processes  into  it,  so  as  to  divide  the  whole  mass  into  numerous 
cells,  which  communicate  so  freely  that  air  injected  will  rapidly  distend  them; 
or  if  one  or  two  openings  be  made  in  this  capsule,  the  whole  of  the  fluid  will 
gradually  escape;  anteriorly  the  crystaline  lens  is  connected  to  this  humor 
by  the  hyaloid  membrane  separating  into  two  laminae  ; external  to  the  lens, 
the  ciliary  processes  and  the  intervening  pigment  mark  it  in  a striated  manner, 
like  the  disk  of  a flower ; this  appearance,  therefore,  has  been  called  the  ciliary 
disk,  or  corona  ciliaris : the  vitreous  humor  serves  to  support  and  expand 
the  retina,  and  the  other  tunics  of  the  eye,  also,  in  transmitting  the  rays  of 
light  from  the  lens,  it  prevents  their  too  rapid  convergence,  and  thus  causes 
an  image  of  larger  size  to  be  painted  on  the  retina. 

§ 5. — Of  the  Shin. 

The  integument  of  the  body  is  composed  of  one  continued  membrane, 
which  is  very  dense,  at  the  same  time  very  extensible ; at  the  several  orifices, 
it  is  continuous  with  the  mucous  membranes,  a vascular  line  alone  marks  the 
distinction  between  them:  by  maceration  or  putrefaction  the  skin  may  be 


216 


THE  DUBLIN  DISSECTOR, 


divided  into  three  laminae,  the  cuticle,  rete  mucosum,  and  cutis  vera.  The 
cuticle  or  epidermis  is  the  external  layer  of  the  skin,  it  is  dry,  thin,  and  trans- 
parent, and  destitute  of  nerves  and  vessels,  it  is  most  intimately  connected 
to  the  cutis  by  numerous  fine  hairs  which  pass  through  it,  also  by  the  several 
exhalant  and  absorbent  vessels  that  open  on  its  surface  by  very  minute  pores ; 
in  some  situations  it  is  very  dense  and  opaque,  as  in  the  hands  and  feet ; it  is 
continued  as  a very  fine  pellicle  into  the  different  orifices,  and  can  be  traced 
for  a considerable  distance  on  the  mucous  membranes,  thus,  from  the  lips  it 
extends  over  the  pharynx  and  along  the  oesophagus  as  far  as  the  cardiac  ori- 
fice of  the  stomach,  where  it  terminates  in  a fimbriated  margin ; from  the 
external  ear  it  extends  along  the  meatus  externus,  and  covers  the  membrana 
tympani ; interiorly  also  it  is  continued  along  the  mucous  lining  of  the  urethra, 
vagina,  and  rectum ; the  cuticle  serves  to  defend  certain  parts  of  the  body 
from  pressure,  to  protect  its  surface  from  contact,  and  to  prevent  evaporation. 
The  rete  mucosum  is  a thin  vascular  lamina,  adhering  to  the  cutis,  connected 
to  it  by  vessels,  it  has  a villous  appearance,  and  is  tinged  with  a mucous  fluid, 
which  presents  different  shades  of  color  in  different  situations  and  in  different 
individuals  ; the  peculiar  complexion  or  color  of  the  body  depends  upon  this 
secretion : in  the  negro,  it  is  very  thick  and  black,  while  the  cuticle  is  trans- 
parent and  the  cutis  vascular  and  red  ; some  anatomists  divide  the  rete  mu- 
cosum into  two,  and  some  even  into  three  or  four  laminae.  The  cutis  vera, 
dermis  or  chorion,  is  much  more  dense  than  either  of  the  preceding  laminae, 
it  is  very  tough  and  strong,  in  some  situations  more  so  than  in  others ; its 
internal  surface  is  cellular,  its  external  is  smooth  and  very  vascular,  it  is  also 
highly  sensible,  particularly  in  some  situations,  as  in  the  fingers  and  toes, 
where  numerous  nerves  are  distributed  to  it  in  the  form  of  small  conical  or 
oval  papillae  ; these  are  very  distinct  at  the  end  of  each  finger,  they  are  very 
vascular,  and  into  each  a nervous  filament  can  be  traced,  in  these  papillae  the 
sense  of  touch  more  particularly  resides.  The  subcutaneous  cellular  tissue 
is  connected  to  the  deep  surface  of  the  cutis,  which  is  itself  cellular;  the  cel- 
lular membrane  is  considered  by  some  as  a part  of  the  integuments ; in  some 
parts  of  the  body,  particularly  if  exposed  to  pressure,  the  cells  are  filled  with 
adeps,  in  other  situations,  where  the  parts  are  subject  to  motion,  the  cells  are 
very  loose,  and  only  contain  a fine  serous  exhalation;  the  former  species  of 
cellular  membrane  has  been  named  adipose  membrane,  the  latter  reticular 
membrane. 


PART  III. 


ANATOMY  OF  THE  VASCULAR  SYSTEM. 

UNDER  THIS  HEAD  WE  MAY  CONSIDER  THE  ANATOMY  OF  THE  ARTERIES,  VEINS, 

AND  LYMPHATICS. 


CHAPTER  I. 

ANATOMY  OF  THE  ARTERIES. 

The  principal  blood-vessels  have  been  already  described  in  the  anatomy  of 
the  different  regions ; in  the  present  section  the  arteries  shall  be  considered  in 
a systematic  manner,  commencing  with  the  aorta,  and  tracing  its  branches 
through  all  parts  of  the  body. 

Aorta  arises  from  the  upper  part  of  the  left  ventricle,  opposite  the  4th  or 
5th  dorsal  vertebra,  (see  page  44,)  ascends  obliquely  forwards  and  to  the  right 
side,  then  turns  backwards  and  to  the  left,  and  then  descends  along  the  dorsal 
vertebra; ; it  thus  forms  the  arch  which  terminates  on  the  left  side  of  the  4th 
vertebra : the  thoracic  aorta  descends  along  the  left  side  of  the  remaining 
dorsal  vertebrae,  inclining  a little  to  their  fore-part  interiorly,  and  passes 
between  the  crura  of  the  diaphragm : the  abdominal  aorta  descends  on  the 
lumbar  vertebrae,  as  far  as  the  4th  or  5th,  where  it  divides  into  the  two  common 
iliac  arteries.  The  aorta  is  at  first  covered  by  the  pericardium  and  the  pul- 
monary artery ; as  it  ascends  it  lies  between  this  vessel  and  the  vena  cava ; 
the  arch  lies  on  the  trachea  a little  above  its  division,  and  on  the  bodies  of  the 
£d  and  3d  vertebrae.  In  the  posterior  mediastinum  the  aorta  descends  on  the 
left  of  the  thoracic  duct  and  vena  azygos,  and  rather  behind  the  oesophagus 
In  the  abdomen  it  lies  between  the  crura  of  the  diaphragm  and  the  psoas 
muscles,  on  the  left  side  of  the  vena  cava  and  behind  the  vena  porta,  the 
pancreas  and  the  peritonaeum.  From  the  arch  of  the  aorta  five  arteries  arise, 
the  right  and  left  coronary,  the  innominata,  the  left  carotid,  and  left  sub- 
clavian. 

The  right  and  left  coronary  arteries  arise  above  two  of  the  sigmoid  valves ; 
the  right  proceeds  along  the  base  towards  the  right  side  of  the  heart,  divides 
into  several  long  branches,  which  supply  the  parietes  of  the  right  auricle 
and  ventricle,  and  communicate  with  the  left  coronary : the  left  descends  ob- 
liquely along  the  left  side  of  the  heart  supplying  the  parietes  of  the  left 
auricle  and  ventricle,  and  communicating  with  the  former  around  the  base 
and  apex  of  the  heart. 

28  31 7 


218 


THE  DUBLIN  DISSECTOR, 


The  arteria  innominata  arises  from  the  tipper  part  of  the  arch,  ascends 
obliquely  to  the  right  side,  in  front  of  the  trachea,  and  behind  the  sterno 
thyroid  muscle,  and  the  left  vena  innominata ; opposite  the  sternal  end  of 
the  clavicle  it  divides  into  the  right  subclavian  and  right  carotid  arteries. 

The  right  and  left  carotid  arteries ; the  right  arises  from  the  arteria 
innominata,  the  left  from  the  arch  of  the  aorta;  these  vessels  ascend  obliquelv 
outwards  as  high  as  the  os  hyoides,  opposite  which  each  divides  into  the 
internal  and  external ; in  this  course  they  are  covered  inferiorly  by  the  sterno- 
mastoid,  hyoid,  and  thyroid,  and  omo-hyoid  muscles;  and  superiorly,  only 
by  the  skin,  platysma,  and  fascia;  the  left  is  also  covered  inferiorly  by  the 
sternum  and  the  vena  innominata,  and  at  its  origin  differs  from  the  right  in 
lying  on  the  trachea,  thoracic  duct  and  oesophagus,  but  after  this  both  ascend 
in  front  of  the  longus  colli  and  rectus  capitis  muscles,  the  inferior  thyroid 
artery,  and  the  recurrent  and  sympathetic  nerves,  and  are  enclosed  in  a sheath 
©f  cellular  membrane,  along  with  and  to  the  tracheal  side  of  the  vagus  nerve 
and  the  internal  jugular  vein. 

The  external  carotid  artery  ascends  obliquely  backwards  to  the  fore-part 
©f  the  meatus  auditorus,  covered  by  the  skin,  platysma,  and  fascia,  also,  by 
the  lingual  nerve,  digastric  and  stylo-hyoid  muscles,  the  parotid  gland  and 
portio  dura  nerve  ; it  lies  superficial  to  the  internal  carotid,  stylo-pharvngeus, 
and  stylo-glossus  muscles,  the  glosso-pharyngeal  nerve,  and  part  of  the  parotid 
gland;  it  gives  off  the  following  arteries,  anteriorly,  the  superior  thyroid, 
lingual,  and  labial;  posteriorly,  the  muscular,  auricular,  and  occipital;  supe- 
riorly, the  pharyngeal,  transverse  facial,  temporal,  and  internal  maxillary. 

The  superior  thyroid  artery  arises  opposite  the  cornu  of  the  thyroid  cartilage, 
descends  obliquely  forwards  and  inwards  beneath  the  sterno-thyroid,  and  omo- 
hyoid muscles,  and  sends  off  the  following  branches  : — 1st,  the  superficial, 
distributed  to  the  integuments  and  superficial  muscles ; 2d,  the  laryngeal, 
accompanying  the  superior  laryngeal  nerve  between  the  os  hyoides  and  thy- 
roid cartilage,  and  distributed  to  the  muscles  and  mucous  membrane  of  the 
larynx ; 3d,  hyoidean,  small  and  irregular,  to  the  lower  border  of  the  os  hyoides 
and  adjacent  muscles  ; and  4th  superior  thyroid,  is  distributed  to  the  thyroid 
gland. 

The  lingual  artery  arises  immediately  above  the  preceding,  it  ascends  tortu- 
ously and  obliquely  forwards  and  inwards,  above  the  os  hyoides  to  the  base 
of  the  tongue,  between  the  hyo  and  the  genio-hyo-glossi  muscles,  and  then  runs 
horizontally  forwards  towards  the  tip  of  the  tongue;  it  gives  oft’  the  following 
branches,  1st,  hyoidean,  small  and  irregular ; 2d,  dorsalis  linguae,  which 
ascends  to  the  dorsum  of  the  tongue,  and  is  lost  on  the  mucous  membrane, 
near  its  base,  also  on  the  velum  and  fauces;  3d,  sublingual,  passes  forwards 
and  outwards  to  the  sublingual  gland,  mylo-hyoid  muscle,  and  mucous  mem- 
brane of  the  mouth ; and  4th,  ranine , which  continues  along  the  lingualis 
muscle  to  the  tip  of  the  tongue. 

The  labial  or  external  maxillary  artery  arises  opposite  the  os-hyoides, 
ascends  obliquely  forwards  behind  the  digastric  and  between  the  submaxillary 
gland  and  the  base  of  the  jaw,  turns  round  the  latter  anterior  to  the  masseter 
muscle,  and  then  ascends  obliquely  forwards  and  inwards  towards  the  side  of 
the  nose ; in  the  neck  it  gives  off,  1st,  inferior  palatine,  which  ascends  along 
the  side  of  the  pharynx,  and  supplies  the  velum  and  the  amygdala;  the  branch 


OR  MANUAL  OF  ANATOMY. 


219 


to  the  latter  often  arises  distinctly ; 2nd,  glandular  to  the  submaxillary  and 
adjoining  lymphatic  glands  ; 3rd,  sub-mental  runs  along  the  mylo-hyoid 
muscle  to  the  chin,  and  supplies  the  surrounding  muscles.  On  the  face  it 
gives  off,  4th,  inferior  labial  to  the  muscles  and  integuments  between  the  lip 
and  the  chin;  5th,  the  inferior  and  superior  coronary , these  run  along  the 
border  of  the  lips  close  to  the  mucous  membrane  and  directly  join  those  from 
the  opposite  side ; 6th,  lateralis  nasi  to  the  muscles  and  skin  on  the  side  and 
dorsum  of  the  nose ; and  7th,  angulciris , which  communicates  with  the 
ophthalmic. 

The  muscular  artery  descends  obliquely  backwards,  divides  into  several 
branches,  which  are  principally  distributed  to  the  sterno-mastoid  muscle  and 
to  the  surrounding  cellular  tissue  and  glands. 

The  occipital  artery  arises  opposite  the  labial,  ascends  obliquely  backwards 
behind  the  digastric,  then  curves  horizontally  backwards  between  the  mastoid 
process  and  the  atlas,  and  near  the  mesial  line  it  ascends  on  the  occiput : it 
gives  off  several  muscular  branches,  some  to  the  mastoid  and  trapezius  muscles, 
several  to  the  deep  muscles  on  the  side  and  back  of  the  neck,  and  on  the  occiput 
it  divides  into  tortuous  branches,  which  ascend  in  different  directions  in  the 
scalp,  and  inosculate  with  the  different  arteries  in  that  region. 

The  posterior  auricular  artery  arises  above,  often  in  common  with  the 
occipital ; it  ascends  behind  the  parotid  and  between  the  meatus  auditoris 
and  the  mastoid  process ; it  divides  into  several  branches  which  are  lost  in  the 
integuments  of  the  ear  and  in  the  scalp. 

The  inferior  or  ascending  pharyngeal  artery  arises  near  the  division  of 
the  common  carotid,  ascends  vertically  to  the  base  of  the  skull,  and  sends  off 
several  phaj-yngeal  and  palatine  branches,  and  ends  in  a small  branch  that 
passes  through  the  foramen  lacerum  posterius,  and  supplies  the  dura  mater 
at  the  base  of  the  cranium. 

The  transverse  artery  of  the  face  arises  from  the  carotid  in  the  parotid 
gland,  accompanies  the  duct  of  Steno,  and  is  distributed  to  the  muscles  and 
integuments  of  the  face,  and  joins  the  branches  of  the  facial  artery. 

The  temporal  artery  ascends  through  the  parotid  gland  between  the  meatus 
auditories  and  the  articulation  of  the  maxilla,  behind  the  zygoma,  and  divides 
on  the  temporal  fascia  into  an  anterior  and  posterior  branch;  it  gives  off,  1st, 
branches  to  the  gland  ; 2nd,  anterior  auricular  ; 3rd,  the  middle  temporal; 
this  pierces  the  fascia  and  is  distributed  to  the  temporal  muscle  ; 4th,  the  an- 
terior or  frontal  supplies  the  skin  and  muscles  of  the  forehead,  and  joins  the 
ascending  branches  of  the  ophthalmic  artery  ; 5th,  posterior  temporal  bends 
backwards  and  upwards  in  the  scalp  and  inosculates  with  the  occipital  and 
auricular  arteries. 

The  internal  maxillary  artery  ascends  obliquely  lorwards  behind  the  neck 
of  the  maxilla,  between  the  pterygoid  muscles,  then  between  the  external 
pterygoid  and  the  temporal  muscle ; it  then  bends  down  into  the  pterygo- 
maxillary  fossa;  it  gives  off  the  following  branches,  1st,  while  internal  to  the 
neck  of  the  maxilla,  the  middle  artery  of  the  dura  mater  ; this  ascends  to  the 
base  of  the  cranium,  passes  through  the  spinous  hole  of  the  sphenoid  bone, 
then  runs  outwards  and  forwards,  and  again  ascends  along  the  great  wing  of 
the  sphenoid  bone  to  the  inferior  angle  of  the  parietal,  which  bone  it  grooves 
very  deeply;  it  then  ascends  between  this  bone  and  the  dura  mater,  divides 


220 


THE  DUBLIN  DISSECTOR, 


into  several  branches,  which  ascend  obliquely  backwards,  and  are  lost  in  the 
bone  and  the  dura  mater ; 2d,  the  inferior  dental  arises  opposite  the  last,  de- 
scends obliquely  forwards  between  the  bone  and  the  internal  lateral  ligament, 
enters  the  dental  foramen,  and  proceeds  beneath  the  teeth,  to  the  roots  of  which 
it  sends  very  small  arteries,  and  through  the  mental  hole  it  sends  a small 
branch  to  the  muscles  and  mucous  membrane,  and  to  inosculate  with  branches 
of  the  labial  artery;  between  the  ptei-ygoid  muscles  it  sends  off,  3rd  the  deep 
temporal  branches,  one  posterior,  the  other  anterior  ; these  supply  the  muscle 
and  ascend  close  to  the  bone  ; 4th,  masseteric;  5th, pterygoid ; 6th,  buccal, 
to  the  buccinator  muscle,  the  fat  and  integuments  of  the  cheek ; Tth,  superio  r 
dental,  which  winds  round  the  maxillary  tuberosity  and  sends  branches  into 
the  alveoli  and  to  the  gums;  in  the  spheno-maxillary  fossa  it  gives  off,  8th, 
infra-orbital,  which  passes  along  the  canal  of  that  name,  is  distributed  to  the 
muscles  of  the  face,  and  communicates  with  the  arteries  of  that  region  ; 9th, 
nasal  passes  inwards  through  the  spheno-palatine  hole,  and  is  distributed  to 
the  mucous  membrane  on  the  spongy  bones  and  on  the  septum ; 10th,  the 
superior  palatine  descends  along  the  posterior  palatine  canal,  and  is  distri- 
buted to  the  muscles  and  to  the  mucous  membrane  of  the  palate,  principally 
to  the  hard  palate;  11th  the  vidian;  this  is  a small  branch  which  passes 
backwards  and  takes  the  course  of  the  first  part  of  the  vidian  nerve  ; these 
terminating  branches  of  the  internal  maxillary  artery  are  entangled  with  the 
divisions  of  the  superior  maxillary  nerve. 

The  internal  carotid  artery  ascends  along  the  vertebral  column  and  the 
side  of  the  pharynx  from  the  common  carotid,  posterior  and  external  to  the 
external  carotid,  behind  the  digastric  and  styloid  muscles,  internal  to  the 
jugular  vein  and  anterior  to  the  vagus  and  sympathetic  nerves,  to  the  foramen 
caroticum  in  the  petrous  bone ; it  then  bends  tortuously  fonvards,  upwards, 
and  inwards,  through  the  carotid  canal,  accompanied  by  the  superior  branches 
of  the  sympathetic,  enters  the  cavernous  sinus,  through  which  it  makes  two 
remarkable  turns  internal  to  the  sixth  pair  of  nerves,  and  arriving  at  the  ante- 
rior clinoid  process,  it  bends  upwards  and  backwards,  and  a little  outwards, 
and  opposite  the  internal  extremity  of  the  fissure  of  Sylvius  it  divides  into  its 
three  terminating  branches,  it  first  gives  off  the  ophthalmic  artery ; in  the 
neck,  and  in  the  carotid  canal,  it  sends  small  and  unimportant  branches  to 
the  surrounding  parts. 

The  ophthalmic  artery  arises  close  to  the  anterior  clinoid  process,  passes 
forwards  through  the  optic  foramen,  below*  the  optic  nerve  and  external  to  it ; 
in  the  orbit  it  rises  above  this  nerve  and  twines  round  it  to  the  inner  side  of 
this  cavity,  along  which  it  passes  to  the  inner  canthus,  where  it  terminates; 
while  on  the  outer  side  of  the  optic  nerve  it  sends  oft",  1st,  centralis  retinae, 
very  small,  pierces  the  sheath  of  the  optic  nerve,  passes  along  the  centre  of  the 
latter,  into  the  eye,  where  it  divides  into  delicate  ramifications  ; these  spread 
along  the  internal  layer  of  the  retina,  and  one  or  two  pierce  the  vitreous 
humour,  and  extend  to  the  capsule  of  the  lens;  2nd,  the  lachrymal  passes  along 
the  external  rectus  muscle,  and  supplies  the  lachrymal  gland,  and  the  external 
part  of  the  palpebrae:  while  above  the  optic  nerve  it  gives  off:  3rd  the  supra- 
orbital, which  passes  forwards  along  the  levator  palpebrae,  and  though  the 
superciliary  notch,  supplies  the  muscles  and  integuments  of  the  eye-brow,  and 
ascending  on  the  forehead,  divides  into  several  branches,  which  are  distributed 


OR  MANUAL  OF  ANATOMY. 


£21 


to  the  scalp,  and  communicate  with  the  temporal  and  occipital  arteries ; 4th,  the 
posterior  ciliary,  ten  or  twelve  in  number,  very  small  surround  the  optic  nerve, 
and  pierce  the  back  part  of  the  sclerotic ; pass  between  it  and  the  choroid,  and 
are  distributed  to  the  latter ; some  of  their  branches  continue  as  far  as  the 
ciliary  processes  and  the  iris;  5th,  long  ciliary  one  on  each  side;  they  pass 
horizontally  forwards,  between  the  sclerotic  and  choroid  membranes,  as  far 
as  the  ciliary  circle ; here  they  divide,  and  form  a circular  inosculation  round 
the  circumference  of  the  iris,  from  this  several  branches  radiate  inwards,  and 
again  unite  in  a circle  near  the  pupil ; 6th,  muscular  arteries,  to  the  different 
muscles  in  the  orbit;  7th,  ethmoidal,  passes  through  the  posterior  orbital  fora- 
men to  the  mucous  membrane  in  the  ethmoid  cells;  8 th,  superior  and  inf erior 
palpebral,  to  the  palpebrae,  caruncula,  conjunctiva,  and  lachrymal  sac; 
9th,  nasal,  passes  beneath  the  trochlea,  along  the  side  of  the  nose,  and 
inosculates  with  the  labial  artery;  10th , frontal,  ascends  to  the  eye-brow  and 
forehead. 

The  posterior  communicating  artery  arises  from  the  carotid,  opposite  the 
ophthalmic ; passes  backwards  and  inwards  external  to  the  corpora  mamil- 
laria,  and  joins  the  posterior  cerebral  artery;  this  artery  forms  the  lateral 
part  of  the  circle  of  Willis  ; it  sends  several  branches  to  the  surrounding  pia 
mater. 

The  anterior  cerebral  artery,  or  arteria  callosa,  passes  forwards  and  in- 
wards above  the  optic  nerve;  anastomoses  with  the  opposite,  by  a short  trans- 
verse branch,  (the  anterior  communicating  artery,)  it  then  bends  upwards  and 
backwards  round  the  corpus  callosum,  on  which  it  terminates  by  dividing  into 
branches  for  the  corresponding  hemisphere  of  the  cerebrum. 

The  middle  cerebral  artery,  very  large,  passes  outwards  in  the  fissure  of 
Sylvius,  and  divides  into  two  tortuous  branches,  which  supply  the  anterior 
and  middle  lobes  of  the  cerebrum.  (Seepage  180.) 

The  subclavian  arteries  ; the  right  arises  from  the  arterial  innominata,  and 
proceeds  nearly  transversely  outwards,  between  the  scaleni  muscles,  then 
obliquely  downwards  and  outwards  behind  the  clavicle ; it  is  covered  at  first 
by  the  sterno-mastoid,  hyoid,  and  thyroid  muscles ; by  the  internal  jugular  vein, 
the  vagus,  and  branches  of  the  sympathetic  nerve ; next,  by  the  phrenic  nerve 
and  anterior  scalenus  muscle,  and  externally  only  by  the  skin,  platysma,  and 
fascia;  it  first  passes  over  the  recurrent  nerve,  the  longus  colli  muscle,  and 
sympathetic  nerve ; next,  the  pleura  and  middle  scalenus  muscle,  and  lastly, 
the  first  rib.  The  left  subclavian  arises  from  the  posterior  part  of  the  arch 
of  the  aorta,  ascends  nearly  vertically  out  of  the  chest;  then  turns  out- 
wards and  downwards  between  the  scaleni  muscles,  and  over  the  first  rib ; 
in  the  chest  this  artery  lies  very  deep,  and  is  covered  by  the  pleura  and  the 
lung,  also  by  the  vena  innominata,  the  vagus,  the  sternum,  and  the  muscles 
attached  to  it ; it  lies  near  the  vertebras,  along  the  side  of  the  oesophagus  and 
thoracic  duct;  in  the  rest  of  its  course,  its  relations  are  similar  to  those  of  the 
right ; each  sends  off  the  following  branches,  vertebral,  thyroid  axis,  internal 
mammary,  superior  intercostal  and  deep  cervical. 

The  vertebral  artery,  arises  from  the  upper  and  back  part  of  the  subclavian; 
ascends  behind  the  inferior  thyroid  artery,  enters  the  foramen  in  the  trans- 
verse process  of  the  5th  or  6th  cervical  vertebra,  and  ascends  through  the 
several  foramina  in  the  superior  vertebrae  as  high  as  the  second ; it  then  bends 


222 


THE  DUBLIN  DISSECTOB, 


backwards  and  outwards;  passes  through  the  foramen  in  the  transverse 
process  of  the  atlas : it  then  turns  backwards  and  inwards,  round  the  articu- 
lation of  this  vertebra  with  the  condyle,  and  pierces  the  dura  mater;  it  then 
ascends  obliquely  inwards  and  forwards  between  the  olivary  and  pyramidal 
bodies,  and  at  the  lower  edge  of  the  pons  it  unites  with  the  opposite,  to  form 
the  basilar  artery;  in  this  course  it  gives  small  branches  to  the  spinal  nerves 
and  to  the  inter- vertebral  muscles : at  the  foramen  magnum  it  gives  off,  1st  and 
second,  the  posterior  and  anterior  spinal  arteries,  which  descend  all  along 
the  spinal  cord ; 3d,  the  inferior  cerebellar  artery  often  arises  from  the  basilar ; 
it  runs  tortuously  around  the  medulla  oblongata,  below  the  vagus,  and  sends 
its  numerous  branches  to  the  inferior  surface  of  the  cerebellum. 

The  basilar  artery,  is  formed  by  the  confluence  of  the  two  vertebral ; it 
ascends  into  the  median  groove  on  the  pons  varolii,  sends  small  branches 
to  the  surrounding  membrane,  and  at  the  upper  edge  of  that  body  it 
divides  into  four  branches,  two  for  each  side,  1st  the  superior  cerebellar  artery, 
passes  outwards  and  backwards,  to  the  upper  surface  of  each  hemisphere  of 
the  cerebellum  on  which  it  spreads  its  branches,  2d,  the  posterior  cerebral 
artery , this  receives  the  posterior  branch  of  the  internal  carotid,  bends  back- 
wards and  outwards,  and  spreads  its  ramifications  on  the  posterior  lobe  of  the 
cerebral  hemisphere.  (See  page  221.) 

The  thyroid  axis,  arises  from  the  upper  part  of  the  subclavian  close  to  the 
scalenus  and  phrenic  nerve,  it  immediately  divides  into  the  four  following 
branches; — 1st,  the  inferior  thyroid,  ascends  tortuously  behind  the  common 
carotid,  then  bends  downwards  and  inwards,  sends  branches  to  the  trachea, 
oesophagus,  &c.  and  is  distributed  to  the  thyroid  gland,  in  which  it  inosculates 
with  the  superior  thyroid,  and  with  the  arteries  of  the  opposite  side ; 2d,  the 
ascending  cervical  ascends  along  and  is  distributed  to  the  anterior  scalenus, 
longus  colli,  and  rectus  capitis  anticus  major  muscles ; 3d,  suprascapular 
runs  obliquely  outwards  and  downwards  beneath  the  clavicle,  passes  above 
the  notch  in  the  superior  costa  of  the  scapula,  supplies  the  supra-spinatus 
muscle  descends  beneath  the  acromion  process  to  the  infra-spinatus  and  teres 
minor  muscles  : 4th,  transversalis  colli  ascends  obliquely  outwards  round 
the  scaleni  muscles,  and  beneath  the  trapezius,  it  divides  into  two  branches, 
one,  the  cervicalis  superficialis,  supplies  the  superficial  muscles  on  the  side 
and  back  part  of  the  neck ; the  other,  the  posterior  scapular  artery,  descends 
beneath  the  levator  anguli  scapulas,  and  the  rhomboid  muscles  along  the  base 
of  the  scapula  as  far  as  the  inferior  angle,  where  it  inosculates  with  the  sub- 
scapular artery  ; the  posterior  artery  of  the  scapula,  as  also  the  supra-capsular 
in  many  subjects,  arise  distinctly  from  the  subclavian  artery. 

The  internal  mammary  artery  arises  opposite  the  thyroid  axis,  it  descends 
obliquely  forwards  and  inwards,  between  the  cartilages  of  the  ribs  and  the 
pleura,  as  far  as  the  ensiform  cartilage,  it  gives  branches  to  the  pleura,  peri- 
cardium, and  mediastinum,  a long  branch  to  the  diaphragm,  which  accompanies 
the  phrenic  nerve,  also  intercostals  ; it  terminates  by  sending  branches  to  the 
diaphragm,  and  to  the  abdominal  muscles,  the  latter  inosculate  with  the 
epigastric  artery. 

The  superior  intercostal  artery  arises  between  the  scaleni,  descends  behind 
the  pleura,  in  front  of  the  neck  of  the  1st  and  2d  ribs,  and  supplies  the  two 
first  pair  of  intercostal  muscles. 


OR  MANUAL  OF  ANATOMY. 


223 


The  cervicalis  profunda  arises  opposite  the  last,  ascends  obliquely  back- 
wards and  outwards,  between  the  transverse  processes  of  the  6th  and  7th  cer- 
vical vertebrae,  and  ascending  on  the  back  of  the  neck,  supplies  the  complexus 
and  the  other  deep  muscles  in  that  region,  and  inosculates  with  the  descending 
branches  of  the  occipital  artery. 

The  axillary  artery  descends  from  the  lower  edge  of  the  first  rib,  obliquely 
outwards  to  the  tendon  of  the  latissimus  dorsi  muscle,  it  is  covered  by  the  in- 
teguments, and  at  first  by  the  external  border  of  the  great  pectoral  muscle, 
lower  down  by  the  great  and  lesser  pectoral,  and  still  lower  down  by  the  ten- 
don of  the  great  pectoral  only ; it  passes  over  the  first  intercostal,  and  serratus 
magnus  muscles,  the  brachial  plexus,  the  sub-scapular  and  the  tendons  of  the 
latissimus  dorsi  and  teres  major  muscles;  the  axillary  vein  descends  along  its 
inner  and  anterior  part,  and  the  brachial  plexus  lies  posterior  and  external  to 
it,  it  sends  off  the  following  arteries,  the  thoracica  acromialis,  the  superior 
and  long  thoracic,  the  sub-scapular,  the  posterior,  and  anterior  circumflex. 

The  •acromoial  thoracic  artery  arises  from  the  front  of  the  axillary  below 
the  subclavian  muscle,  above  the  lesser  pectoral,  and  opposite  the  fissure 
between  the  great  pectoral  and  deltoid  muscles;;  it  divides  into  several 
branches,  which  pass  some  to  the  pectoral  muscles,  others  to  the  acromion 
process,  deltoid  muscle,  and  integuments  of  the  shoulder  and  arm,  one  long 
branch  accompanies  the  cephalic  vein. 

The  superior  thoracic  artery  arises  a little  below  the  preceding,  some- 
times in  common  with  it,  it  passes  forwards  and  inwards,  and  divides  into 
branches  which  supply  the  cellular  membrane  and  glands  in  the  axilla,  the 
pectoral  muscles,  the  breast,  and  the  integuments. 

The  long  thoracic  artery  arises  below  the  lesser  pectoral,  descends  ob- 
liquely forwards  along  the  side  of  the  chest,  parallel  to  the  lower  edge'  of  the 
great  pectoral,  to  which  it  sends  some  branches,  it  terminates  in  the  inter- 
costal muscles  and  integuments,  and  inosculates  with  the  internal  mammary 
and  the  intercostal  arteries. 

The  sub-scapular  artery  arises  opposite  to  and  descends  along  the 
lower  edge  of  the  sub-scapular  muscle,  and  soon  divides  into  an  anterior  and 
posterior  branch ; the  former  continues  to  descend  along  the  back  part  of  the 
axilla,  and  supplies  the  sub-scapular,  serratus  magnus,  and  latissimus  dorsi 
muscles ; the  latter  passes  backwards  round  the  inferior  costa  of  the  scapula, 
behind  the  long  tendon  of  the  triceps  ; and  above  the  latissimus  and  teres  ma- 
jor muscles,  it  is  distributed  on  the  dorsum  of  the  scapula  to  the  infra-spina- 
tus  and  teres  minor  muscles,  and  inosculates  with  the  supra-scapular  artery. 

The  posterior  circumflex  artery  arises  below  the  last,  sometimes  in  com- 
mon with  it,  it  passes  out  of  the  axilla  between  the  long  tendon  of  the  triceps 
and  the  humerus,  turns  round  this  bone  between  it  and  the  deltoid  muscle,  to 
which  last  it  sends  numerous  branches. 

The  anterior  circumflex  artery  is  smaller  than  the  preceding,  and  arises 
either  from  it  or  from  the  axillary  ; it  passes  outwards  round  the  anterior  part 
of  the  humerus,  beneath  the  deltoid,  coraco-brachialis,  and  biceps ; to  these 
muscles  it  sends  its  branches;  it  also  sends  one  long  branch  along  the  bici- 
pital groove  to  the  synovial  membrane  of  the  shoulder  joint. 

The  brachial  artery  descends  obliquely  outwards  to  the  bend  of  the 
elbow,  where  it  divides  into  the  radial  and  ulnar  arteries ; it  is  covered  by 


224 


THE  DUBLIN  DISSECTOR, 


the  skin  and  brachial  aponeurosis,  and  inferiorlj  by  the  fascia  of  the  biceps, 
and  the  median  basilic  vein;  it  lies  on  the  inner  side  of  the  coraco-brachialis 
and  biceps,  and  passes  over  the  upper  part  of  the  triceps,  the  coraco-brachialis, 
and  the  brachiseus  anticus  ; it  is  accompanied  by  a vein  on  either  side,  also, 
by  the  median  nerve,  which  above  lies  to  its  outer,  and  below  to  its  inner  side, 
it  passes  superficial  to  the  artery  about  the  middle  of  the  arm;  in  addition  to 
several  muscular  branches  it  sends  otf  the  superior  and  inferior  profunda,  and 
the  anastomotica. 

The  superior  profunda  arises  below  the  teres  major,  accompanies  the 
musculo-spiral  nerve  obliquely  downwards  and  outwards,  between  the  three 
heads  of  the  triceps,  and  in  the  musculo-spiral  groove  of  the  humerus ; it 
divides  into  two  large  branches,  one  descends  in  the  triceps  to  the  olecranon, 
the  other  accompanies  the  radial  nerve  to  the  outer  condyle,  and  communicates 
with  the  radial  recurrent  artery. 

The  inferior  profunda  arises  opposite  the  tendon  of  the  coraco-brachialis, 
descends  on  the  surface  of  the  triceps,  along  with  the  ulnar  nerve,  to  the 
inner  condyle,  and  communicates  with  the  ulnar  recurrent. 

The  anastomotica  arises  about  two  inches  above  the  joint,  passes  inwards, 
supplying  the  adjacent  muscles,  and  inosculating  with  the  preceding  and 
with  the  ulnar  recurrent  arteries. 

In  the  triangular  hollow  at  the  bend  of  the  elbow,  the  brachial  artery  divides 
into  the  radial  and  ulnar. 

The  ulnar  artery  is  the  larger  of  the  two.it  descends  along  the  ulnar  side 
of  the  fore-arm  to  the  palm  of  the  hand,  covered  superiorly  by  the  superficial 
flexors  and  pronators,  and  by  the  median  nerve ; inferiorly  by  the  skin  and 
fascia,  overlapped,  however,  by  the  tendons  of  the  flexor  digitorum  sublimis 
and  flexor  carpi  ulnaris,  between  which  it  descends  to  the  wrist;  it  passes 
over  the  brachiseus  anticus,  flexor  profundus,  pronator  quadratus,  the  annular 
ligament  of  the  carpus  and  the  flexor  tendons  in  the  palm  of  the  hand  ; it  is 
accompanied  by  two  veins,  and  by  the  ulnar  nerve,  the  latter  descends  along 
its  ulnar  side;  it  gives  off,  1st,  the  anterior  ulnar  recurrent  which  ascends 
in  front  of  the  inner  condyle,  on  the  brachiasus  anticus,  and  inosculates  with 
the  anastomotica;  2d,  the  posterior  ulnar  recurrent  large  and  tortuous, 
ascends  behind  the  inner  condyle,  along  the  ulnar  nerve,  and  anastomoses 
with  the  anastomotica  and  inferior  profunda  arteries;  3d,  inter-osseal 
artery,  passes  backwards  and  divides  into  an  anterior  and  posterior  branch  ; 
the  anterior  inter-osseal  artery  descends  along  the  fore-part  of  the  inter- 
osseal membrane,  beneath  the  deep  flexors,  pierces  that  membrane  near  the 
pronator  quadratus,  and  descends  on  the  back  part  of  the  carpus,  and  is  dis- 
tributed to  the  carpal  bones,  and  to  the  sheaths  of  the  extensor  tendons;  the 
posterior  inter-osseal  artery  passes  backwards  beneath  the  anconseus,  and 
descends  along  the  back  of  the  fore-arm,  sending  its  branches  to  the  extensor 
muscles ; this  artery  superiorly  sends  a very  large  recurrent  branch  in  the 
anconteus  muscle  to  the  olecranon,  to  communicate  with  the  superior  pro- 
funda; 4th,  muscular  branches  to  the  two  layers  of  flexor  muscles,  and  to 
the  skin;  5th,  dorsalis  carpi  ulnaris  turns  round  the  lower  end  of  the  ulna, 
and  spreads  its  branches  on  the  back  part  of  the  wrist  and  hand;  6th,  super- 
ficial palmar , forms  the  palmar  arch,  bends  obliquely  across  the  palm  of  the 
hand  towards  the  thumb,  and  inosculates  with  branches  of  the  radial  artery : 


OR  MANUAL  OF  ANATOMY. 


225 


7th,  ramus  profundus,  passes  beneath  the  flexor  tendons,  crosses  the  5th 
and  6th  metacarpal  bones,  and  joins  the  deep  palmar  branch  of  the  radial 
artery,  and  thus  completes  the  deep  palmar  arch;  from  the  superficial  arch 
long  digital  branches  pass,  these  divide  and  supply  the  opposite  sides  of  all 
the  fingers,  except  the  radial  side  of  the  index  finger  and  the  thumb. 

The  radial  artery  continues  in  the  direction  of  the  brachial  artery;  it 
passes  along  the  radial  side  of  the  fore-arm  to  the  wrist,  turns  round  the  ex- 
ternal lateral  ligament  of  this  joint,  then  passes  forwards  between  the  heads 
of  the  two  first  metacarpal  bones  into  the  palm  of  the  hand,  and  terminates  in 
three  branches  ; in  the  fore-arm  it  is  covered  by  the  skin  and  fascia  onlv,  lies 
between  the  supinator  longus  externally,  and  the  pronator  teres,  and  flexor 
carpi  radialis  internally  ; it  passes  over  the  bi-ceps,  supinator  brevis,  pronator 
teres,  flexor  digitorum  sublimis,  flexor  pollicis,  and  pronator  quadratus  ; it  is 
accompanied  by  two  veins,  and  the  radial  nerve  is  to  its  external  side  in  the 
middle  of  the  fore-arm;  on  the  outer  side  of  the  wrist  it  is  covered  by  the  ex- 
tensor tendons  of  the  thumb,  and  on  the  back  of  the  hand  by  the  skin  and 
fascia,  it  gives  off,  1st,  radial  recurrent,  large  and  tortuous,  bends  outwards 
and  upwards  along  the  supinators  and  extensors,  to  which  it  sends  several 
branches,  and  inosculates  with  the  superior  profunda  ; 2d,  muscular  branches 
to  the  flexors  and  supinators;  Sd,  superfcialis  volse  passes  over  the  annular 
ligament  of  the  carpus,  supplies  the  small  muscles  of  the  thumb,  and  inoscu- 
lates with  the  ulnar  artery  ;4th,  dorsalis  carpi  radialis;  5 th,  dor  sales  pol- 
licis, these  branches  are  distributed  as  their  names  imply ; 6th,  radialis  indicis, 
runs  along  the  radial  side  of  the  fore-finger;  7th,  magna  pollicis  runs  along 
the  first  metacarpal  bone,  and  divides  into  two  bi’anches,  which  pass  along  the 
opposite  sides  of  the  thumb  to  its  last  phalanx ; 8th,  pahnaris  profunda  passes 
across  the  metacarpal  bones,  joins  the  deep  branch  of  the  ulnar,  and  thus 
forms  the  deep  palmar  arch,  from  which  several  branches  proceed  to  the 
inter-osseal  muscles,  and  to  the  bones  and  ligaments  of  the  metacarpus. 

The  Thoracic  Aorta  gives  off'  the  bronchial,  oesophageal,  and  intercostal 
arteries. 

The  bronchial  arteries  are  two  or  three  in  number,  they  arise  from  the  fore- 
part of  the  aorta,  below  the  arch  ; they  pass  to  either  side,  enter  the  back  part 
of  the  root  of  each  lung,  and  are  lost  in  the  cellular  tissue  of  these  organs; 
these  arteries  sometimes  arise  from  the  intercostal,  they  are  very  irregular  in 
number  and  size. 

The  oesophageal  arteries  are  also  irregular,  generally  three  or  four  in  num- 
ber ; they  arise  from  different  parts  of  the  aorta,  send  branches  to  the  medias- 
tinum and  oesophagus ; on  the  latter  some  ascend,  others  descend  ; the  former 
inosculate  with  the  cervical  arteries,  the  latter  with  the  abdominal. 

The  intercostal  arteries,  in  general  ten  on  the  left,  nine  on  the  right  side, 
the  superior  intercostal  on  the  right  side  being  larger  than  that  on  the  left ; 
they  arise  from  the  back  part  of  the  aorta,  pass  obliquely  outwards  behind  the 
pleura,  and  enter  the  intercostal  spaces,  run  along  the  lower  edge  of  each  rib 
between  the  layers  of  muscles,  and  about  the  middle  of  the  chest  divide  into 
an  inferior  and  superior  branch ; the  former,  smaller,  runs  along  the  superior 
border  of  the  lower  rib : the  latter  continues  in  the  groove  in  the  upper ; they 
both  supply  the  intercostal  muscles  and  send  branches  through  these  to  the 
29 


226 


THE  DUBLIN'  DISSECTOR, 


pleura  and  to  the  superficial  muscles  of  the  chest;  they  inosculate  with  the 
internal  mammary  and  with  the  thoracic  arteries.  Each  intercostal  artery, 
before  it  enters  the  intercostal  space,  sends  a large  branch  backwards 
between  the  transverse  process  of  the  vertebrae  to  the  muscles  on  the  posterior 
part  of  the  trunk,  these  dorsal  branches  of  the  intercostal  arteries  also  send 
small  branches  through  the  inter-vertebral  holes  along  the  spinal  nerves  to  the 
medulla  spinalis. 

The  Abdominal  Aorta  sends  off  the  following  branches : the  phrenic, 
coeliac  axis,  superior  mesenteric,  inferior  mesenteric,  renal,  supra-renal, 
spermatic,  lumbar,  and  middle  sacral. 

The  phrenic  arteries  arise  in  common,  or  near  each  other,  from  the  fore- 
part of  the  aorta ; they  both  send  branches  to  the  supra-renal  capsules  and  to 
the  crura  of  the  diaphragm;  the  right  ascends  behind  the  vena  cava;  the  left 
behind  the  oesophagus;  on  the  diaphragm  each  divides  into  an  external  and 
internal  branch  ; the  former  passes  towards  the  circumference  of  the  muscle, 
and  inosculates  with  the  internal  mammary  and  the  inferior  intercostals ; the 
latter  encircles  the  central  tendon,  communicates  with  its  fellow  and  with  the 
phrenic  branches  of  the  mammary. 

The  cceliac  axis  arises  from  the  fore-part  of  the  aorta  opposite  the  last  dor- 
sal vertebra;  it  soon  divides  into  three  branches,  1st,  the  gastric  artery 
ascends  obliquely  to  the  left  side,  to  the  cardiac  orifice,  to  which  and  to  the 
cesophagus  it  sends  several  branches;  it  then  bends  along  the  lesser  curvature 
towards  the  right  side  between  the  laminae  of  the  lesser  omentum,  and  inoscu- 
lates with  the  superior  pyloric  artery;  it  sends  its  branches  to  the  anterior 
and  posterior  surfaces  of  the  stomach ; 2d,  hepatic  artery  ascends  obliquely 
towards  the  right  side,  in  front  and  to  the  left  side  of  the  vena  porta  ami 
ductus  choledochus,  and  in  the  transverse  fissure  of  the  liver,  divides  into 
right  and  left  hepatic  arteries;  in  this  course  it  gives  off  the  superior  pyloric. 
which  passes  along  the  upper  surface  of  the  pylorus  and  joins  the  gastric 
artery;  and  the  gastro-duoclcnalis  which  descends  between  the  pylorus  and 
the  duodenum;  this  gives  off  inferior  pyloric  branches,  and  divides  into  the 
pancreatico-duodenalis  and  gcislro-epiploicu  dextra : the  former  takes  a curved 
course  between  the  duodenum  and  the  pancreas,  sending  branches  to  each, 
and  inosculates  with  the  superior  mesenteric  artery;  the  latter  turns  for- 
wards, and  to  the  left  side  along  the  great  curvature  of  the  stomach,  between 
it  and  the  laminae  of  the  great  omentum,  to  which,  as  well  as  the  stomach,  it 
sends  numerous  branches,  and  inosculates  with  the  gastro-epiploica  sinistra, 
a branch  of  the  splenic  artery ; the  right  and  left  hepatic  arteries  then  separate 
and  plunge  into  the  substance  of  the  liver,  accompanying  the  branches  of  the 
vena  porta:  the  right  hepatic  is  the  larger,  and  before  it  enters  the  gland  it 
gives  off  the  cystic  artery  which  supplies  the  parietes  of  the  gall-bladder ; 3d, 
the  splenic  artery  is  the  longest  branch  of  the  coeliac  axis  ; it  passes  backwards 
and  to  the  left  side  along  the  upper  edge  of  the  pancreas,  to  which  it  sends 
several  branches;  near  the  spleen  it  gives  oft’  the  gastro-epiploica  sinistra; 
this  bends  forwards,  and  to  the  right  side  along  the  great  curvature  of  the  sto- 
mach, and  between  the  laminae  of  the  great  omentum,  it  inosculates  with  the 
corresponding  branch  from  the  hepatic  artery  ; the  splenic  next  sends  off  the 
vasa  brevia,  five  or  six  small  branches  which  pass  to  the  great  end  of  the 


OR  MANUAL  OF  ANATOMY. 


227 


stomach,  and  inosculate  with  the  proper  gastric  arteries;  the  splenic  artery 
then  divides  into  several  branches,  which  enter  the  foramina  on  the  concave 
surface  of  the  spleen,  and  ramify  through  its  spongy  substance. 

The  superior  mesenteric  artery  arises  a little  below  the  cceliac,  descends 
obliquely  forwards  and  to  the  left  behind  the  pancreas,  and  over  the  duode- 
num ; it  then  passes  between  the  layers  of  the  mesentery  and  takes  an  arched 
course  towards  the  right  iliac  fossa : from  its  concave  side  arise  three  branches, 
the  ilio-colic,  right  colic,  and  middle  colic;  these  three  branches  proceed 
between  the  lamina  of  the  meso-colon  to  the  large  intestine,  each  divides  into 
two  branches,  which  unite  with  those  on  either  side,  and  form  arches,  from 
the  convexities  of  which  branches  arise,  some  of  which  subdivide  and  unite 
again  in  the  same  manner  as  the  first  branches ; near  tire  intestine  straight 
branches  proceed  on  the  anterior  and  posterior  surface,  and  supply  the  mus- 
cular and  mucous  coats ; from  the  convex  side  of  the  mesenteric  artery  eigh- 
teen or  twenty  branches  arise,  these  proceed  between  the  laminae  of  the 
mesentery,  divide,  and  form  arches,  from  which  new  branches  arise,  these 
again  divide,  and  again  unite  in  an  arched  manner;  these  divisions  and  sub- 
sequent inosculations  occur  three  or  four  times  before  the  arteries  arrive  at 
the  intestine ; near  the  latter  each  branch  divides  into  two,  which  proceed  in 
a direct  course,  one  on  the  anterior,  the  other  on  the  posterior  surface  of  the 
intestine,  and  are  distributed  principally  to  the  mucous  membrane. 

The  inferior  mesenteric  artery  arises  about  two  inches  below  the  pre- 
ceding; it  descends  towards  the  left  iliac  fossa  and  divides  into  three 
branches,  left  colic,  sigmoid,  and  superior  haetnorrhoidal ; the  left  colic 
ascends  in  the  left  meso-colon,  anastomoses  with  the  middle  colic  branch  of  the 
superior  mesenteric,  and  supplies  the  left  part  of  the  colon  ; the  sigmoid  ar- 
tery is  distributed  to  the  sigmoid  flexure  of  the  colon;  the  superior  hemor- 
rhoidal descends  along  the  back  part  of  the  rectum,  supplies  the  coats  of  this 
intestine,  and  inosculates  with  the  middle  and  inferior  hsemorrhoidal  arteries. 

The  renal  arteries  arise  from  the  sides  of  the  aorta,  between  the  superior 
and  inferior  mesenteric  arteries;  the  right  is  longer  than  the  left;  it  passes 
across  the  spine  behind  the  vena  cava ; both  pass  behind  their  corresponding 
vein  and  divide  near  the  kidney  into  five  or  six  brandies,  which  ramify 
through  the  substance  of  this  gland. 

The  capsular  arteries  are  two  or  three  in  number;  they  arise  either  from 
the  renal  arteries  or  from  the  aorta;  they  supply  the  renal  capsules. 

The  spermatic  arteries  arise  from  the  fore-part  of  the  aorta;  the  left  fre- 
quently arises  from  the  renal  artery;  they  are  long  and  tortuous,  descend 
obliquely  outwards,  crossingin  front  of  the  psoas  muscle  and  the  ureter ; in  the 
male  they  accompany  the  vas  deferens  through  the  inguinal  canal,  and  sup- 
ply the  testicle  and  epididymis;  in  the  female  they  pass  to  the  ovarium,  and 
also  send  branches  to  the  Fallopian  tubes,  and  to  the  sides  of  the  uterus. 

The  lumbar  arteries  me  four  or  five  pair;  they  arise  from  the  back  part 
of  the  aorta,  pass  obliquely  outwards  through  the  psoas,  send  branches 
between  the  transverse  processes  of  the  lumbar  vertebrae,  to  the  muscles  of 
the  back  and  loins,  and  terminate  in  the  abdominal  muscles. 

The  middle  sacral  artery  arises  from  the  back  part  of  the  aorta  a little  above 
the  bifurcation ; it  descends  nearly  in  the  median  line  close  to  the  sacrum. 


228 


THE  DUBLIN  DISSECTOR, 


sends  its  branches  to  this  bone,  and  communicates  with  the  lateral  sacral 
arteries. 

The  common  iliac  arteries  descend  obliquely  outwards  as  far  as  the  ilio- 
sacral  articulations,  opposite  which  each  divides  into  the  internal  and  extern?.! 
iliac;  the  right  iliac  is  longer  than  the  left,  and  passes  over  the  commence- 
ment of  the  vena  cava. 

The  internal  iliac  or  hypogastric  artery  passes  downwards  and  forwards 
into  the  pelvis  to  the  side  and  back  part  of  the  bladder,  where  it  ends  in  a 
ligamentous  substance,  which  ascends  first  along  the  side  of  the  bladder,  and 
then  behind  the  recti  muscles  as  far  as  the  umbilicus  ; the  internal  iliac  artery 
gives  off  the  following  branches,  ilio-lumbar,  lateral  sacral,  hemorrhoidal, 
vesical,  uterine  and  vaginal,  the  glutsel,  sciatic,  obturator,  and  pudic.  1st, 
The  ilio-lumbar  arises  from  the  back  part  of  the  internal  iliac,  passes  out- 
wards behind  the  external  iliac  vessels  and  the  psoas  muscle,  into  the  sub- 
stance of  the  iliacus  internus,  in  which  it  divides  into  ascending  and  descend- 
ing branches.  2nd,  The  lateral  sacral  descends  obliquely  inwards  in  front  of 
the  sacral  holes,  through  which  it  sends  branches  to  the  spinal  nerves,  also  to 
the  pyriform  muscle,  and  to  communicate  with  the  middle  sacral.  3rd,  The 
heemorrhoidal  are  two  or  three  branches  of  uncertain  origin,  they  pass  to  the 
sides  of  the  rectum  and  communicate  with  the  superior  and  inferior  haemor- 
rhoidal  arteries.  4th,  The  vesical  arteries  arise  from  the  iliac,  or  from  some  of 
its  branches;  they  ramify  on  the  coats  of  the  bladder;  the  inferior  also  supply 
the  parts  about  the  neck  of  tins  organ.  5th,  The  uterine  and  vaginal  arteries 
either  arise  from  the  internal  iliac  or  from  some  of  its  branches,  and  are  distri- 
buted as  their  names  imply.  6th,  The  glutxal  artery  passes  backwards  and 
outwards  from  the  pelvis  by  the  upper  part  of  the  sciatic  notch,  above  the 
pyriform  muscle,  and  divides  into  several  branches,  some  of  which  supply  the 
glut3sus  maximus,  others  pass  forwards  in  a semicircular  course  towards  the 
spine  of  the  ilium,  and  supply  the  glutseus  medius  and  minimus  muscles. 
7th,  The  obturator  artery  passes  out  of  the  pelvis  by  the  superior  part  of  the 
thyroid  hole  into  the  upper  part  of  the  thigh  beneath  the  pectinasus,  and  divides 
into  several  branches  to  supply  the  obturator  and  adductor  muscles.  8th,  The 
sciatic  artery  passes  over  the  pyriform  muscle  and  escapes  from  the  pelvis  by 
the  lower  part  of  the  sciatic  notch,  along  with  the  sciatic  nerve;  it  sends 
several  branches  to  the  glutseus  maximus,  the  hamstrings,  and  adductor 
tnagnus  ; also  to  the  small  capsular  muscles  and  to  the  sciatic  nerve;  these 
communicate  with  the  circumflex  and  perforating  arteries.  9th,  The  internal 
pudic  artery  smaller  than  the  preceding,  leaves  the  pelvis  along  with  it  below 
the  pyriform  muscle,  re-enters  the  cavity  between  the  sciatic  ligaments,  and 
then  ascends  obliquely  inwards  and  forwards  along  the  tuber  and  ramus  of  the 
ischium  and  ramus  of  the  pubis,  and  a little  below  the  symphysis  pubis  divides 
into  two  branches.  In  the  pelvis  the  pudic  at  first  gives  small  branches  to  the 
adjoining  viscera;  as  it  is  passing  round  the  spine  of  the  ischium,  and 
between  the  sciatic  ligaments,  it  gives  small  branches  to  the  surrounding 
ligaments  and  muscles;  when  it  has  re-entered  the  pelvis  it  gives  oft',  1st, 
external  hxmorrhoidal  arteries,  two  or  three,  they  pass  transversely  to  the  side 
of  the  rectum  and  anus,  and  supply  the  integuments  and  muscles  in  that  region  ; 
2nd,  the  perinxal  artery  first  descends,  then  turns  forwards  and  upwards 


OR  MANUAL  OF  ANATOMY. 


229 


round  the  transversus  perinrei,  proceeds  along  the  perinseum,  and  is  distri- 
buted to  the  muscles  and  integuments  in  this  situation,  and  to  the  scrotum  ; 
3rd,  transversalis perinasi,  a small  branch  arising  near  to  and  often  from  the 
preceding;  it  takes  the  course  of  the  muscle  of  that  name,  and  is  lost  in  the 
muscles  and  integuments ; 4th,  artery  of  tlic  bulb , passes  transversely 
between  the  layers  of  the  triangular  ligament,  enters  the  spongy  substance  of" 
the  bulb,  and  spreads  its  branches  through  the  corpus  spongiosum  urethra ; 
5th  and  6th  artery  of  the  corpus  cavernosum  and  dorsalis  penis;  the 
former  enters  and  extends  along  the  corpus  cavernosum,  the  latter  along  the 
dorsum  of  the  penis  as  far  as  the  glans.  In  the  female  the  pudic  artery  gives 
off  branches  to  the  perinaeum  and  labia,  and  to  the  corpus  cavernosum  and 
dorsum  of  the  clitoris,  analogous  to,  but  smaller  than  those  in  the  male. 

The  external  iliac  artery  proceeds  from  the  common  iliac  downwards 
and  outwards  to  Poupart’s  ligament,  beneath  which  it  passes  and  receives  the 
name  of  femoral ; it  lies  along  the  inner  side  of  the  psoas,  the  vein  is  internal 
and  posterior  to  it,  it  gives  off  near  the  groin  two  branches ; 1st,  circumfiexa 
ilii  arises  from  its  outer  side,  ascends  obliquely  outwards  as  far  as  the  crest 
of  the  ilium  where  it  divides  into  several  branches,  some  pass  to  the  abdominal 
muscles,  others  to  the  iliacus  internus  and  quadratus  lumborum,  and  commu- 
nicate with  the  ilio-lumbar  artery  ; 2nd,  the  epigastric  artery  arises  from  its 
fore-part,  a little  above  Poupart’s  ligament,  it  at  first  descends,  then  turns 
forwards  and  ascends  between  the  abdominal  muscles  and  the  peritonaeum, 
crosses  behind  the  spermatic  cord,  a little  internal  to  the  internal  inguinal 
ring;  about  three  or  four  inches  above  the  pubis  it  enters  the  sheath  of  the 
rectus,  divides  into  branches  which  ascend  in  this  muscle  to  the  umbilicus, 
and  inosculate  with  the  mammary  artery. 

The  femoral  artery,  or  the  continuation  of  the  external  iliac,  descends 
obliquely  inwards  from  the  middle  of  the  crural  arch,  along  the  anterior  and 
internal  part  of  the  thigh,  covered  superiorly  by  the  skin,  superficial  fascia, 
inguinal  glands  and  fascia  lata  : in  the  middle  of  the  thigh  it  is  also  covered 
by  the  sartorius,  and  beneath  this  by  a strong  aponeurosis  connecting  the 
vastus  internus  to  the  tendons  of  the  adductor  longus  and  magnus,  at  the 
inferior  part  of  the  middle  third  of  the  thigh,  it  passes  obliquely  backwards 
through  a tendinous  opening,  bounded  externally  by  the  vastus  internus, 
internally  by  the  adductor  magnus,  superiorly  by  the  adductors  magnus 
and  longus,  and  interiorly  by  the  adductor  magnus  and  vastus  internus ; the 
femoral  artery  first  passes  over  the  psoas  and  iliacus,  next  over  the  pecti- 
nseus  and  short  adductor,  from  which  it  is  separated  by  a quantity  of  cellular 
membrane  and  by  small  vessels,  it  next  passes  over  the  tendon  of  the  adductor 
longus  ; the  femoral  vein  descends  along  with  it,  at  first  internal,  afterwards 
posterior  to  it ; the  anterior  crural  nerve  is  external  to  it,  two  or  three  of  its 
branches  are  very  near  it,  above  the  middle  of  the  thigh,  one  small  nerve 
crosses  the  artery,  and  the  saphenus  nerve  descends  in  its  sheath  along  the 
fore-part  of  the  vessel ; it  sends  off,  1st,  three  or  four  superficial  branches,  viz.: 
inguinal  branches  to  the  inguinal  glands,  &c. ; the  superficial  pudic,  one  or 
two  in  number,  which  pass  towards  the  pubis  and  are  lost  in  the  integuments  ; 
the  superficial  epigastric  the  longest  and  largest  of  these  branches,  ascends 
obliquely  inwards  towards  the  umbilicus,  parallel  to  the  internal  epigastric, 
and  is  lost  in  the  integuments  ; the  external  circumflex  ilii  extends  along 


250 


THE  DUBLIN  DISSECTOR, 


Poupart5s  ligament  to  the  crest  of  the  ilium,  where  it  terminates  in  the  skin  ; 
2nd,- the  profunda  is  the  largest  branch  of  the  femoral,  it  arises  about  two 
inches  below  the  crural  arch,  from  the  outer  and  back  part  of  the  feim  ral 
artery,  bends  a little  outwards  at  first,  then  descends  obliquely  inwards  ar.d 
backwards  behind  the  femoral  artery,  and  the  tendon  of  the  adductor  longus, 
passing  over  the  psoas,  crurieus,  and  adductor  brevis,  at  the  back  part  of  the 
thigh  it  terminates  in  two  branches  for  the  hamstring  muscles;  in  this  course 
it  gives  off  the  two  circumflex,  and  the  three  perforating  branches ; the  ex- 
ter  rial  circumflex  artery,  arises  from  the  outer  part  of  the  profunda,  passes 
transversely  beneath  the  sartorius  and  rectus  muscles,  and  divides  into  three 
fasciculi  of  branches,  superior,  middle,  and  inferior,  the  first  ascend  along  the 
tensor  vaginas  and  glutseus  medius  muscles,  and  inosculate  with  the  glut  teal 
artery,  the  second  pass  round  the  bone  to  its  back  part,  and  inosculate  with 
the  glutasal,  sciatic,  and  internal  circumflex  arteries  ; the  third  are  the  longest 
and  largest  branches,  they  descend  towards  the  knee  and  supply  the  extensor 
muscles.  The  internal  circumflex  artery  arises  sometimes  below,  sometimes 
above  the  preceding,  it  often  proceeds  from  the  femoral  itself,  it  passes  back- 
wards between  the  psoas  and  pectinmus,  along  the  obturator  externus  tendon, 
to  the  back  part  of  the  thigh,  first  sending  off  several  branches  to  the  surround- 
ing muscles,  and  to  the  hip  joint,  also  some  to  inosculate  with  the  obturator 
artery;  at  the  back  of  the  thigh  it  gives  several  branches  to  the  gemelli. 
quadratus,  gluteus  maximus,  and  the  hamstrings,  and  inosculates  with  the 
external  circumflex  and  sciatic  arteries  ; the  first  or  superior  perforating  artery 
passes  backwards  beneath  the  lesser  trochanter,  between  the  pectinseus  and 
adductor  brevis,  and  through  the  adductor  magnus,  its  branches  are  distributed 
to  the  latter  and  to  the  hamstrings;  the  second  or  middle  perforating  artery 
larger  than  the  first,  passes  through  the  adductor  brevis  and  magnus,  and 
spreads  its  branches  among  the  muscles  on  the  back  of  the  thigh ; the  third 
or  inferior  perforating  artery  descends  behind  the  adductor  longus,  and 
through  the  magnus  to  the  hamstrings  ; on  the  back  part  of  the  thigh  the  pro- 
funda ends  in  two  branches,  one  passes  to  the  biceps,  the  other  to  the  semi- 
membranosus.. 

After  the  origin  of  the  profunda,  the  femoral  gives  off  several  small  muscu- 
lar and  cutaneous  twigs,  and  near  the  opening  in  the  triceps,  though  which 
it  passes,  it  gives  off,  3rd,  the  anastomotica  magna ; this  descends  in  front  of 
the  adductor  tendon  to  the  knee,  sends  several  branches,  to  the  integuments, 
vastus  interims,  and  to  the  patella;  these  inosculate  with  the  long  branches 
of  the  external  circumflex  artery  above,  and  with  the  articular  arteries 
below. 

The  popliteal  artery  descends  from  the  inner  side  of  the  femur,  oblique!  v 
outwards  to  the  inferior  and  central  part  of  the  popliteal  space ; it  is  covered 
bv  the  skin  and  fascia,  and  overlapped  superiorly  by  the  semi-membranosus, 
and  inferiorly  by  the  gastrocnemius  and  plantaris  muscles;  the  popliteal  vein 
lies  superficial  and  external  to  it ; the  sciatic  nerve  is  still  more  superficial 
and  external;  its  branches  are,  1st,  several  muscular  branches  to  the  ham- 
strings and  to  the  gastrocnemius;  2nd,  superior  articular  encircle  the  lower 
extremity  of  the  femur,  turn  round  the  sides,  to  the  fore-part  of  the  joint,  and 
communicate  with  the  anastomotica  and  with  the  branches  of  the  external  cir- 
cutnflex;  3rd,  azygos -articular  passes  forwards  through  the  posterior  ligament 


OR  MANUAL  of  anatomy. 


231 


of  the  joint,  and  supplies  the  synovial  membrane  and  the  adipose  substance  in 
its  cavity ; 4th,  inferior  articular  arteries,  encircle  the  lower  part  of  the  joint;  the 
internal  passes  round  the  head  of  the  tibia,  the  external  is  beneath  the  external 
lateral  ligament;  these  arteries  pass  round  the  joint  to  its  fore-part,  inosculate 
with  the  preceding  and  with  the  anterior  tibial  recurrent;  at  the  lower  part 
of  the  ham  the  popliteal  divides  into  the  anterior  and  posterior  tibial  arteries. 

The  anterior  perforates  the  inter-osseous  space  close  to  the  head  of  the  fibula, 
descends  obliquely  forwards  along  the  inter-osseous  membrane  and  over  the 
lower  part  of  the  tibia,  the  synovial  membrane  of  the  ankle  and  the  superior 
and  internal  part  of  the  tarsus  to  the  first  inter-osseal  space;  in  the  leg  it  is 
overlapped  by  the  tibialis  anticus  internally,  by  the  extensor  communis 
and  extensor  pollicis  externally,  it  passes  beneath  the  annular  ligament  of  the 
ankle ; on  the  tarsus  it  is  covered  by  the  skin  and  by  the  internal  tendon  of 
the  extensor  brevis;  it  is  accompanied  by  two  veins  ; the  anterior  tibial  nerve 
descends  superficial  and  external  to  it ; it  gives  off,  1st,  the  recurrent  which 
passes  upwards  and  inwards,  and  is  lost  around  the  articulation  of  the  knee; 
2nd,  muscular  branches,  very  numerous  to  the  muscles  on  the  outer  and  ante- 
rior part  of  the  leg;  3rd,  malleolar  branches,  which  ramify  on  the  external  and 
internal  malleoli ; .on  the  former  they  inosculate  with  the  anterior  peronseal ; 
4th  and  5th,  tarsal  and  metatarsal  are  distributed  to  the  bones  and  ligaments  of 
the  tarsus  and  metatarsus;  between  the  two  first  metatarsal  bones  it  divides 
into,  6th  and  7th,  the  cirteria pollicis  and  the  communicans ; the  former  supplies 
the  integuments  of  the  great  toe ; the  latter  the  first  inter-osseal  muscle,  and 
inosculates  with  the  plantar  arteries. 

The  posterior  tibial  artery  descends  obliquely  inwards  between  the  superficial 
and  deep  layer  of  muscles  on  the  back  of  the  leg,  to  the  space  between  the 
heel  and  inner  ankle,  where  it  divides  into  the  internal  and  external  plantar 
arteries  ; it  is  covered  by  the  gastrocnemius  and  solasus,  and  lies  on  the  tibialis 
posticus,  flexor  communis,  and  interiorly  on  the  tibia;  it  is  accompanied  by 
two  veins,  and  by  the  posterior  tibial  nerve,  which  lies  to  its  external  side  ; it 
gives  off,  1st,  several  muscular  branches  to  the  deep  and  superficial  muscles; 
2d,  the  peronseal  artery  arises  about  an  inch  below  the  popliteal,  descends 
obliquely  outwards  towards  the  external  ankle  ; between  the  fibula  and  flexor 
pollicis ; sends  numerous  branches  to  the  muscles  of  the  leg,  and  about  two 
inches  above  the  ankle  divides  into  the  anterior  a.x\dposteriorperon(ealhra.nches,; 
the  former  pierces  the  inter-osseous  ligament,  and  inosculates  with  the  exter- 
nal malleolar;  the  latter  spreads  its  branches  on  the  outer  side  of  the  heel  and 
of  the  foot ; between  the  heel  and  inner  ankle  the  posterior  tibial  divides  into  the 
internal  and  external  plantar ; the  internal  plantar  proceeds  along  the  internal 
side  of  the  sole  of  the  foot,  supplying  the  muscles  and  integuments  of  the  great 
toe,  and  inosculating  with  the  adjacent  vessels  both  on  the  dorsum  and  in  the 
sole  of  the  foot;  the  external  plantar  much  larger  than  the  preceding,  passes  for- 
wards and  outwards  above  the  flexor  digitorum  brevis,  as  far  as  the  5th  meta- 
tarsal bone  ; it  then  bends  across  the  metatarsus,  along  the  transversalis  pedis, 
as  far  as  the  1st  metatarsal  bone  where  it  joins  the  anterior  tibial,  and  thus  forms 
the  plantar  arch,  from  which  proceed  numerous  muscular  branches,  and  the 
digital  arteries ; these  last  arise  from  the  anterior  or  convex  edge  of  the  arch 
pass  forwards,  supplying  the  lumbricales  and  interossei  muscles,  and  divide 
each  into  two  branches  to  supply  the  opposite  sides  of  the  toes. 


232 


THE  DUBLIN  DISSECTOR, 


§ 2. — Anatomy  of  the  Veins. 

In  addition  to  the  veins  which  accompany  the  arteries,  the  relative  situation 
of  which  has  been  already  considered,  there  are  also  several  veins  which  run 
independent  of  these,  and  take  a superficial  or  subcutaneous  course.  It  is 
impossible  to  fix  the  exact  point  at  which  a vein  commences  ; it  is  generally 
considered  that  the  arteries  having  terminated  in  minute  ramifications  or  ca- 
pillaries, the  veins  commence  from  these,  so  that  in  reality  each  vein  is  a 
returning  artery  only  altered  in  structure;  some  veins  are  said  to  commence 
from  cells,  as  in  the  spleen  and  corpora  cavernosa  penis  ; we  shall  describe 
the  veins  then  as  proceeding  from  the  extreme  parts  of  the  body  towards  the 
centre  or  towards  the  heart;  and  1st, 

The  veins  of  the  head  and  neck;  the  small  arteries  which  ramifv  on  the 
side  and  lore-part  of  the  scalp  are  accompanied  each  by  two  veins,  these  all 
terminate  in  the  temporal  veins  which  sink  into  the  parotid  gland  and  there 
join  the  internal  maxillary  vein,  which  is  formed  by  the  confluence  of  the 
several  small  veins  which  accompany  the  branches  of  the  internal  maxillary 
artery;  the  union  of  these  two  veins  is  the  commencement  of  the  external 
jugular  vein  which  descends  a little  backwards  nearly  parallel  to  the  fibres 
of  the  platysma,  across  the  sterno-mastoid  muscle,  and  at  a little  distance 
above  the  clavicle  enters  the  subclavian  vein,  or  some  of  its  branches;  near 
the  angle  of  the  jaw  this  vein  receives  a branch  from  the  facial  vein,  and 
in  its  course  down  the  neck  it  is  joined  by  several  cutaneous  branches;  it 
also  not  unfrequently  communicates  with  the  internal  jugular  vein  by  one  or 
two  small  branches  near  the  os  hvoides. 

The  internal  jugular  vein  commences  in  the  foramen  lacerum  posterius 
basis  cranii,  from  the  termination  of  the  lateral  sinus,  it  descends  along  the 
outer  side  of  the  carotid  artery,  receives  the  facial,  laryngeal,  and  several 
muscular  veins,  and  opposite  the  sternal  end  of  the  clavicle  joins  the  sub- 
clavian vein. 

The  veins  of  the  upper  extremity  are  superficial  and  deep,  the  superficial 
are  the  cephalic,  basilic,  and  median. 

The  cephalic  vein  commences  on  the  outer  and  back  part  of  the  carpus  from 
the  junction  of  the  several  dorsal  veins  of  the  hand,  it  ascends  along  the 
radial  side  of  the  fore-arm  to  the  bend  of  the  elbow,  is  there  joined  by  the 
median  cephalic,  it  then  continues  to  ascend  along  the  outer  side  of  the  biceps  ; 
near  the  shoulder  it  turns  forwards  and  passes  towards  the  clavicle  between 
the  pectoral  and  deltoid  muscles,  and  then  sinks  deep  to  join  the  axillary 
vein. 

The  basilic  vein  commences  near  the  lower  end  of  the  ulna,  one  branch 
from  the  little  finger  is  named  the  vena  salvatella,  the  others  are  irregular  in 
number  and  size,  it  ascends  along  the  ulnar  side  of  the  fore-arm,  before  the 
internal  condyle,  where  it  is  joined  by  the  median  basilic  vein,  it  then  con- 
tinues to  ascend  along  the  inner  side  of  the  arm,  accompanying  the  brachial 
vessels,  and  near  the  axilla  it  joins  one  of  the  venae  comites  or  the  axillary 
vein  itself. 

The  median  vein  arises  a little  above  the  wrist,  ascends  along  the  middle 
of  the  fore-arm  to  the  bend  of  the  elbowr,  it  here  divides  into  two  branches. 


OR  MANUAL  Of-  ANATOMY. 


233 


one  (median  basilic)  joins  the  basilic  vein,  the  other  (median  cephalic)  joins  the 
cephalic  vein,  sometimes  a third  branch  joins  one  of  the  deep  veins.  The  deep 
veins  accompany  the  brachial  artery  and  its  branches  in  the  arm  and  fore-ann, 
two  with  each ; these  end  in  the  axillary  vein,  which  ascends  in  front  of  the 
artery,  receives  the  thoracic  veins,  passes  beneath  the  clavicle,  and  is  then 
named  subclavian  vein;  this  passes  inwards,  over  the  anterior  scalenus, 
receives  several  veins  from  the  shoulder  and  side  of  the  neck,  also  the  external 
jugular  and  vertebral  veins,  and  opposite  the  sterno-clavicular  articulation 
unites  with  the  internal  jugular  vein  to  form  the  vena  innominata,  which  on 
the  right  side  is  a short  trunk  that  descends  into  the  thorax  behind  the  sterno- 
thyroid muscle,  and  opposite  the  cartilage  of  the  first  rib  joins  that  from  the 
left  side,  which  is  longer,  and  takes  a more  transverse  course  as  it  enters  the 
chest,  in  front  of  the  trachea,  and  of  the  arteria  innominata ; this  vein  receives 
several  branches  from  the  thyroid  gland  and  from  the  anterior  mediastinum. 
The  vena  cava  superior  or  descendens  commences  opposite  the  first  costal 
cartilage  on  the  right  side,  descends  obliquely  inwards  in  front  of  the  right 
pulmonary  vessels,  enters  the  pericardium,  and  opposite  the  third  or  fourth 
cartilage  it  opens  into  the  right  auricle ; as  it  enters  the  pericardium  it  is  joined 
by  the  vena  azygos  which  commences  by  a small  branch  on  the  first  lumbar 
vertebra,  which  often  communicates  with  the  inferior  vena  cava;  this  vein 
then  ascends  through  the  aortic  opening  of  the  diaphragm  into  the  posterior 
mediastinum  along  the  right  side  of  the  dorsal  vertebras  and  of  the  aorta, 
receiving  the  intercostal  veins  from  each  side,  also  the  oesophageal  and 
bronchial ; at  the  4th  vertebra  it  curves  forwards  round  the  root  of  the  right 
lung,  and  opens  into  the  back  part  of  the  vena  cava. 

The  veins  of  the  lower  extremity  are  superficial  and  deep  ; th e.  former,  the 
internal  and  external  saphena ; the  external  passes  from  the  dorsum  of  the 
foot  behind  the  external  malleolus,  ascends  along  the  back  of  the  leg  to  the 
ham,  and  joins  the  popliteal  vein ; the  internal  saphena  commences  on  the 
upper  and  inner  part  of  the  foot,  ascends  in  front  of  the  inner  ankle  along  the 
inner  side  of  the  leg,  and  behind  the  internal  condyle  of  the  knee ; it  then 
inclines  to  the  internal  and  anterior  part  of  the  thigh,  and  ascends  to  within 
about  two  inches  of  Poupart’s  ligament,  it  then  passes  through  the  saphenic 
opening  in  the  fascia  lata  and  joins  the  femoral  vein  ; the  deep  veins  of  the  leg 
accompany  the  arteries,  two  with  each,  they  terminate  in  the  popliteal  vein, 
which  ascends  superficial  and  external  to  the  artery ; this  vein  then  receives 
the  name  of femoral , and  is  closely  connected  to  the  artery,  lying  posterior  to 
it  below,  and  on  its  inner  side  above ; this  then  passes  behind  the  crural  arch 
and  becomes  the  external  iliac,  which  lies  internal  and  rather  posterior  to  the 
accompanying  artery  ; opposite  the  ilio-sacral  symphysis  this  is  joined  by  the 
internal  iliac  vein,  which  arises  from  the  union  of  the  several  veins  that 
accompany  the  branches  of  the  internal  iliac  artery;  the  union  of  the  exter- 
nal and  internal  iliac  veins  constitute  the  common  iliac  which  ascends  on  each 
side  towards  the  rig-ht  side  of  the  4th  lumbar  vertebra,  and  unite  to  form  the 
inferior  vena  cava  ; the  left  common  iliac  vein  is  longer  than  the  right,  and 
runs  obliquely  across  the  spine ; both  are  posterior  to  the  corresponding  arteries. 
The  inferior  vena  cava  ascends  along  the  right  side,  of  the  lumbar  vertebrae,  on 
the  psoas  and  left  crus  of  the  diaphragm,  to  the  liver,  passes  through  a groove 
in  this  organ  between  the  right  and  middle  lobes,  and  then  through  the  large 
quadrangular  opening  in  the  tendon  of  the  diaphragm  perforates  the  pericardium, 
30 


234 


THE  DUBLIN  DISSECTOR, 


and  opens  into  the  lower  and  back  part  of  the  right  auricle;  it  receives 
the  middle  sacral,  the  spermatic,  the  renal,  and  capsular,  and  lastly  the  hepatic 
and  the  phrenic  veins.  The  vena  portae  receives  the  blood  from  all  the 
abdominal  viscera  except  the  kidneys,  bladder  and  uterus ; a large  vein  com- 
mences on  the  back  of  the  rectum  ( hemorrhoidal ) ascends  towards  the  meso- 
colon and  becomes  the  inferior  mesentric  vein  which  accompanies  the  artery 
of  the  same  name ; about  the  2d  lumbar  vertebra  this  unites  with  the  superior 
mesentric  vein,  which  accompanies  the  artery  of  that  name  also  ; behind  the 
pancreas  this  trunk  is  joined  by  a very  large  vein,  the  splenic,  which  returns 
the  blood  from  the  spleen,  and  also  receives  the  veins  from  the  great  and  lesser 
curvatures  of  the  stomach,  from  the  duodenum  and  pancreas  ; this  large  vein 
passes  transversely  behind  the  pancreas  and  below  the  splenic  artery ; the  vena 
portae  is  formed  by  the  union  of  the  splenic  and  mesenteric  veins,  in  front  of 
the  aorta,  and  behind  the  pancreas  ; it  then  ascends  to  the  right  side,  enclosed 
in  the  lesser  omentum  and  behind  the  hepatic  artery  and  ductus  choledochus; 
in  this  course  it  receives  small  veins  from  the  omentum,  pancreas,  and  gall- 
bladder; at  the  transverse  fissure  it  divides  at  right  angles  into  a right  and 
left  branch,  which  pass  horizontally  for  a short  distance,  and  form  what  is 
termed  the  sinus  of  the  porta ; this  rests  on  the  lobulus  caudatus ; these 
branches  then  enter  the  liver,  and  ramify  through  its  substance  along  with  the 
branches  of  the  hepatic  artery  and  duct,  and  surrounded  by  the  capsule  of 
Glisson. 

The  vena  portae  has  no  valves,  whereas  all  the  veins  of  the  extremities  are 
furnished  with  these,  also  the  superficial  veins  of  the  neck  ; the  deep  veins  of 
the  neck,  the  vena  azygos,  and  the  pelvic  veins,  are  deprived  of  valves  ; the 
coats  of  the  vena  portae  are  more  dense  and  fibrous  than  those  of  most  other 
veins  ; the  femoral  vein  also  possesses  such  a very  dense  structure,  that  when 
divided  it  will  often  remain  open  like  an  artery. 

§ 3. — Anatomy  of  the  Lymphatic  System. 

The  lymphatic  vessels  have  a great  resemblance  to  veins,  they  are  furnished 
with  numerous  valves,  and  are  arranged  in  two  sets,  a superficial  and  deep ; 
both  of  these  accompany  the  veins,  that  is,  proceed  from  the  extreme  parts 
towards  the  centre,  the  greater  number  terminate  in  the  thoracic  duct,  some 
however  end  in  the  veins  on  the  right  side,  and  recent  observations  seem  to 
prove,  that  in  different  situations  the  lymphatic  and  venous  system  are  more 
closely  allied  than  was  formerly  believed ; the  lymphatics  are  extremely 
minute,  in  some  situations  they  cannot  be  demonstrated,  as  in  the  brain,  in  such 
probably  the  veins  perform  the  additional  office  of  absorption  ; it  is  uncertain 
in  what  manner  these  vessels  commence,  whether  by  open  mouths  in  the 
different  structures,  or  whether  they  are  fine  returning  arteries  takipg  the 
same  course  as  the  veins,  and  only  differing  from  the  latter  in  their  delicacy 
of  size,  in  having  more  numerous  valves,  in  not  transmitting  the  colored 
particles  of  blood,  and  in  being  connected  with  the  lymphatic  or  conglobate 
glands. 

The  lymphatics  of  the  lower  extremities  are  superfcial  and  deep,  the  first 
accompany  the  external  and  internal  saphena  veins;  those  which  take  the 
course  of  the  external  saphena,  end  in  the  popliteal  glands,  where  they  unite 
with  the  deep  lymphatic  vessels  which  take  the  course  of  the  tibial  and  fibular 


OR  MANUAL  OF  ANATOMY. 


235 


veins  and  arteries ; the  lymphatics  which  accompany  the  internal  saphena 
vein  ascend  to  the  groin,  pass  through  the  inguinal  glands,  and  communicate 
not  only  with  all  the  deep  lymphatics  of  the  limb,  but  also  with  the  superficial 
vessels  from  the  abdomen,  perinasum,  and  genital  organs  ; the  deep-seated 
lymphatics  about  the  hip  and  the  perimeum  accompany  the  branches  of  the 
internal  iliac  artery  and  vein  into  the  pelvis,  where  they  pass  through  the 
pelvic  lymphatic  glands ; the  lymphatics  from  the  inferior  extremities  and  from 
the  pelvis  ascend  towards  the  spine,  form  a plexus  round  the  iliac  arteries, 
• and  pass  behind  the  aorta  close  to  the  vertebras,  and  terminate  in  the  recepta- 
culum  chyli,  or  the  commencement  of  the  thoracic  duct,  into  which  numerous 
lymphatic  or  lacteal  vessels  open  from  the  intestinal  canal.  The  lacteal  or 
chyliferous  vessels  commence  from  open  mouths  on  the  surface  of  the  intestine, 
and  thence  pass  through  the  mesenteric  glands,  increasing  in  size  and  dimin- 
ishing in  number,  towards  the  spine.  The  lymphatics  of  the  stomach  take  the 
course  of  the  arteries  of  that  viscus,  also  towards  the  spine,  and  join  the  thoracic 
duct.  The  lymphatics  of  the  liver  are  superficial  and  deep,  the  former  are 
very  distinct,  some  pass  back  towards  the  spine,  others  ascend  along  the 
falciform  ligament,  enter  the  thorax,  and  proceed  through  the  anterior  medi- 
astinum to  the  thoracic  duct  near  its  termination  ; tire  deep  lymphatics  pass, 
some  out  of  the  transverse  fissure,  others  from  the  posterior  edge  of  the  liver 
on  the  diaphragm,  all  then  pass  back  towards  the  spine. 

The  thoracic  canal  commences  on  the  body  of  the  2d  or  3d  lumbar  vertebra 
by  a large  dilatation,  named  the  receptaculum  chyli  ; it  then  ascends  between 
the  crura  of  the  diaphragm  into  the  posterior  mediastinum,  and  is  situated  on 
the  right  of  the  aorta,  on  the  left  of  the  vena  azygos,  and  behind  the  oesophagus ; 
' with  these  relations,  it  rises  to  about  the  5th  dorsal  vertebra,  and  then  crosses 
the  spine  obliquely  to  the  left  side,  passing  behind  the  oesophagus  and  the  arch 
of  the  aorta ; it  then  again  ascends,  and  is  placed  beneath  the  left  pleura, 
between  the  left  carotid  and  subclavian  arteries,  and  along  the  left  side  of  the 
oesophagus,  it  rises  into  the  neck,  as  high  as  the  6th  vertebra,  behind  the  carotid 
and  thyroid  arteries,  and  jugular  vein;  itthen  curves  outwards  and  downwards, 
and  opens  into  the  left  subclavian  vein,  close  to  the  jugular.  Two  valves  in- 
ternally protect  this  opening,  these  are  situated  one  at  either  side.  The 
thoracic  duct  receives  in  its  course  along  the  thorax  several  branches  from  the 
lungs,  the  heart,  and  the  parietes  of  the  chest;  in  the  neck,  the  lymphatics  from 
the  left  arm  and  left  side  of  the  head,  face,  and  neck,  open  into  it.  The  lym- 
phatics of  the  upper  extremities  are  superficial  and  deep,  the  former  accompany 
the  sub-cutaneous  veins  to  the  elbow,  and  a little  above  the  bend  of  the  joint 
they  pass  inwards  through  a small  gland  that  is  situated  above  the  inner 
condyle ; they  then  join  the  deep  lymphatics,  and  ascend  along  the  inner  side 
of  the  arm  to  the  axilla,  pass  through  the  axillary  conglobate  glands,  surround 
the  axillary  artery,  and  pass  with  it  beneath  the  clavicle  into  the  neck,  where 
they  are  joined  by  the  lymphatics  from  the  neck  and  shoulder.  On  the  left 
side  these  branches  end  in  the  thoracic  duct ; on  the  right  side  they  form  a short 
canal  (called  the  right  or  lesser  thoracic  duct)  u'hich  opens  into  the  right  or  left 
vena  innominata,  at  the  upper  part  of  the  anterior  mediastinum. 

ANATOMY  OF  THE  FCETAL  CIRCULATION. 

The  umbilical  vein  which  arises  by  numerous  branches  from  the  placenta, 
and  extends  along  the  umbilical  cord,  twisted  round  the  umbilical  arteries. 


236 


THE  DUBLIN  DISSECTOR, 


enters  the  umbilicus  of  the  foetus,  ascends  obliquely  backwards,  enclosed  in 
the  duplicature  of  the  falciform  ligament,  behind  the  lineaalba,  and  the  right 
rectus  muscle  ; it  arrives  at  the  notch  in  the  anterior  edge  of the  liver,  proceeds 
backwards  along  the  horizontal  fissure,  sending  branches  to  either  side,  par- 
ticularly to  the  left  lobe,  which  at  this  period  of  life  is  of  considerable  size. 
When  the  umbilical  vein  arrives  near  the  transverse  fissure,  it  divides  into  two 
branches ; the  right  or  communicating,  the  left  or  the  ductus  venosus,  the 
right  is  the  larger,  it  passes  transversely  for  about  an  inch  and  joins  the  trunk 
of  the  vena  portae ; the  left,  or  the  ductus  venosus,  ascends  between  the  left  and 
spigelian  lobes  towards  the  diaphragm,  and  joins  the  middle  hepatic  veins 
just  as  these  are  about  to  join  the  vena  cava.  The  right  auricle  distended 
with  Wood  from  the  superior  and  inferior  vena  cava,  then  contracts  and  propels 
its  contents  partly  into  the  right  ventricle,  but  principally  through  the  foramen 
ovale  into  the  left  auricle.  From  the  right  ventricle  the  blood  is  propelled  into 
the  pulmonary  artery ; this  vessel  in  the  foetus  divides  into  three  branches,  one 
for  either  lung  small,  and  one  in  the  centre  very  large,  the  ductus  arteriosus, 
this  is  about  half  an  inch  in  length,  passes  backwards  and  downwards, and 
joins  the  aorta  a little  below  its  arch;  but  little  blood  passes  through  the 
lateral  branches,  the  principal  portion  passing  thrugh  the  ductus  arteriosus 
into  the  aorta.  That  portion  of  blood  which  was  transmitted  directly  from  the 
right  auricle,  through  the  foramen  ovale  into  the  left  auricle,  descends  into  the 
left  ventricle,  from  which  it  is  also  propelled  into  the  aorta,  the  superior 
branches  of  which  circulate  the  blood  through  the  upper  parts  of  the  body, 
whence  it  is  returned  to  the  heart  by  the  veins  that  form  the  superior  vena  cava. 
The  descending  aorta  conveys  the  blood  to  the  abdominal  viscera,  and  at  the 
fourth  lumbar  vertebra  this  vessel  divides  into  the  external  and  internal  iliac  arte- 
ries, the  former  is  small  in  the  child,  the  latter  is  very  large,  and  is  named  the 
umbilical  or  hypogastric  artery,  this  passes  forwards  and  upwards  along  the 
side  of  the  bladder,  approaches  its  fellow, and  ascends  to  the  umbilicus  ; these 
arteries  then  twine  around  the  umbilical  vein  in  the  cord,  and  arriving  at  the 
placenta  divide  into  numerous  branches,  which  ramify  through  this  organ; 
these  two  arteries  thus  serve  the  office  of  veins.  The  external  iliac  arteries 
descend  as  in  the  adult,  and  the  blood  which  they  circulate  is  returned  by  the 
corresponding  veins.  The  iliac  veins  unite  at  the  fourth  lumbar  vertebra,  and 
commence  the  inferior  vena  cava,  which  ascends,  and  as  in  the  adult,  passes 
through  the  liver,  is  joined  by  the  hepatic  veins,  and  then  terminates  in  the 
right  auricle  of  the  heart. 

In  connection  with  the  foetal  heart,  the  student  may  remark  th t thymus  gland 
this  body  fills  the  upper  part  of  the  anterior  mediastinum,  ascending  as  high 
as  the  thyroid  gland,  and  descending  in  front  of  the  pericardium,  and  the  great 
vessels,  nearly  as  low  as  the  diaphragm;  it  consists  of  two  lobes  of  an  oval 
figure,  close  in  the  centre,  but  separated  at  either  end.  It  lies  on  the  trachea, 
the  left  vena  innominata,  the  arch  of  the  aorta,  and  the  pericardium,  is 
covered  by  the  sternum  and  steno-thyroid  muscles,  and  is  surrounded  by  a 
loose  capsule  of  cellular  membrane.  It  consists  of  several  small  lobules 
which  are  filled  with  a whitish  fluid.  Several  of  the  organs  of  the  body 
presents  peculiarities  in  the  foetus,  these  have  been  already  noticed  in  the 
description  given  of  each  in  the  adult  state. 


PART  IV 


DISSECTION  OF  THE  JOINTS. 

When  all  the  muscles,  vessels,  nerves,  &c.  have  been  dissected,  the  student 
may  examine  the  anatomy  of  the  joints : in  almost  every  articulation  we  find 
a smooth  and  delicate  membrane  extended  over  the  articulating  surface  of 
each  bone ; this  is  termed  a synovial  membrane,  it  forms  a shut  sac  like  a 
serous  membrane,  and  constantly  contains  a small  quantity  of  glairy  fluid 
termed  synovia ; this  membrane  is  generally  protected  externally  by  ligaments, 
which  also  serve  to  connect  the  bones  together;  these  ligaments  are  termed 
capsular  when  they  surround  the  joint,  as  in  the  shoulder  and  hip ; when 
they  are  confined  to  a particular  part  they  are  termed  accessory  ligaments,  or 
lateral,  anterior , posterior,  &c.  &c. 

TEMPORO-MAXILLARY  ARTICULATIONS. 

Each  condyle  of  the  inferior  maxilla  is  received  into  that  portion  of  the 
glenoid  cavity  of  the  temporal  bone,  which  is  anterior  to  the  fissure,  it  also 
moves  on  the  transverse  root  of  the  zygoma;  this  joint  is  strengthened  by  the 
external  and  internal  lateral  and  the  stylo-maxillary  ligaments,  an  inter- 
articular  cartilage,  two  synovial  membranes,  and  an  imperfect  capsular  liga- 
ment. 

The  external  lateral  ligament  arises  broad  from  the  zygomatic  process  of 
the  temporal  bone,  descends  obliquely  back,  and  is  inserted  narrow  into  the 
outer  side  of  the  neck  of  the  condyle  of  the  lower  jaw. 

The  internal  lateral  ligament  is  thinner  and  longer  than  the  external,  it 
arises  narrow  from  the  spinous  process  of  the  sphenoid  bone,  descends 
obliquely  forwards  and  is  inserted  broad  into  the  orifice  of  the  inferior  dental 
canal. 

The  stylo -maxillary  ligament  is  a thin  aponeurosis,  arises  from  the  styloid 
process  of  the  temporal  bone,  passes  forwards  and  outwards ; is  connected  to 
the  cervical  fascia,  and  to  the  stylo-glossus  muscle,  and  is  inserted  into  the 
angle  of  the  lower  maxilla,  between  the  masseter  and  internal  pterygoid 
muscles,  and  the  parotid  and  sub-maxillary  glands. 

The  synovial  membranes,  one  covers  the  cartilaginous  surface  of  the  zygo- 
matic eminence  and  the  glenoid  cavity,  and  is  reflected  over  the  upper  sur- 
face of  the  inter-articular  cartilage:  the  other,  which  is  smaller,  covers  the 
under  surface  of  the  inter-articular  cartilage,  and  is  reflected  over  the  con- 
dyle ; these  sacs  have  no  communication  with  each  other. 

The  inter-articular  Jibro-cartilage  is  of  an  oval  figure,  thick  in  its  circum- 
ference, thin  ia  the  centre.  Its  upper  surface  is  adapted  to  the  articular 

237 


238 


THE  DUBLIN  DISSECTOR, 


eminence  arid  glenoid  cavity,  and  its  lower  surface  to  the  condyle.  Some 
fibres  of  the  external  pterygoid  are  attached  to  its  forepart,  the  external 
lateral  ligament  also  adheres  to  it:  sometimes  there  is  a hole  in  the  centre  of 
it. 

The  capsular  ligament  consists  of  dense  fibres  which  arise  from  the  zygo- 
matic eminence  and  from  the  glenoid  fissure,  as  they  descend  they  adhere  to 
the  inter- articular  cartilage,  and  are  inserted  into  the  neck  of  the  lower  jaw  ; 
this  ligament  is  deficient  anteriorly,  at  the  insertion  of  the  external  pterygoid 
muscle. 

ARTICULATION  OF  THE  OCCIPUT  WITH  THE  ATLAS  AND  AXIS. 

The  condyles  of  the  occipital  bone  are  received  into  the  superior  oblique 
processes  of  the  atlas,  and  are  attached  by  imperfect  capsular  ligaments,  bv 
synovial  membranes  which  cover  the  opposed  cartilaginous  surfaces,  and  bv 
an  anterior  and  posterior  ligament  which  are  attached  superiorly  to  the  anterior 
and  posterior  edges  of  the  foramen  magnum,  and  inferioriy  to  the  upper  edge 
of  the  atlas,  before  and  behind  its  oblique  processes. 

The  occipital  bone,  though  not  in  contact  with,  is  yet  connected  to  the  axis 
by  the  two  lateral  or  moderator  ligaments,  and  by  the  apparatus  ligamentosus 
colli. 

The  lateral  ligaments  arise  from  each  side  of  the  odontoid  process,  ascend 
obliquely  outwards,  and  are  inserted  into  the  inner  side  of  each  condyle. 

The  apparatus  ligamentosus  (or  the  perpendicular  ligament  of  some  anato- 
mists) is  a flat  fasciculus  of  fibres,  which  descend  from  the  lower  part  of  the 
cuneiform  process,  behind  the  odontoid  process,  and  is  inserted  into  the  supe- 
rior part  of  the  transverse  ligament  of  the  atlas  in  the  middle,  and  into  the 
bodies  of  the  second  and  third  vertebra  on  either  side,  on  these  it  becomes 
continuous  with  the  posterior  common  vertebral  ligament. 

ARTICULATION  BETWEEN  THE  ATLAS  AND  AXIS. 

These  two  vertebras  are  not  only  connected  by  synovial  membranes  and 
fibrous  bands  around  these,  and  by  a ligament  anteriorly  and  posteriorly  as  in 
all  the  other  vertebra,  but  the  odontoid  process  is  also  secured  in  the  atlas  by 
a transverse  ligament  and  synovial  membranes. 

The  transverse  ligament  describes  the  fourth  of  a circle,  it  is  thick  and 
fibro-cartilaginous  in  the  centre,  is  attached  on  each  side  to  the  inner  edge  of 
each  oblique  process  of  the  atlas,  and  is  connected  in  the  centre  by  some  of 
the  fibres  of  the  apparatus  ligamentosus.  to  the  cuneiform  process  superiorly, 
and  to  the  body  of  the  axis  inferioriy  ; there  is  also  a synovial  sac  connected 
to  the  posterior  surface  of  the  odontoid  process,  and  to  the  anterior  surface 
of  this  ligament;  another  synovial  membrane  covers  the  opposed  cartilaginous 
surfaces  of  the  atlas  and  the  processus  dentatus:  by  means  of  these  several 
ligaments  all  rotatory  motion  between  the  occiput  and  the  first  vertebra  is 
prohibited,  whereas  between  the  atlas  and  the  axis  it  can  occur  freely. 


OR  MANUAL  OF  ANATOMY. 


239 


THE  COMMON  ARTICULATIONS  OF  THE  VERTEBRAE. 

The  bodies  of  the  vertebrae  are  united  by  an  anterior,  a posterior,  and  inter- 
• vertebral  ligaments. 

The  Anterior  Vertebral  Ligament  is  a strong  band  of  fibres  extending  from 
the  axis  to  the  sacrum,  and  adhering  to  the  bones  and  inter-vertebral  sub- 
stances: beneath  this  band  other  fibres  are  seen  crossing  obliquely  between 
the  bodies  of  the  vertebrae.  This  ligament  is  narrow  in  the  cervical  and  lum- 
bar regions,  broader  and  more  distinct  in  the  dorsal ; it  consists  of  three  planes 
of  fibres,  viz.  the  superficial  extend  over  four  or  five  vertebrae ; the  middle 
over  two  or  three,  and  the  third  only  cover  a single  vertebra. 

The  Posterior  Vetebral  Ligament  extends  down  the  back  part  of  the  bodies 
of  the  vertebrae,  along  the  front  of  the  spinal  canal ; it  consists  of  smooth 
glistening  fibres ; it  is  narrow  in  the  dorsal,  and  broad  in  the  lumbar  and  cer- 
vical regions. 

The  Inter-vertebral  Ligaments  or  Fibre -cartilages  are  placed  between  the 
bodies  of  all  the  vertebrae,  except  between  the  atlas  and  dentata.  They  are 
united  very  firmly  above  and  below  to  the  flat  surfaces  of  the  vertebrae.  In 
the  neck  and  loins  they  are  thicker  in  front  than  behind,  the  contrary  in  the 
back ; they  are  formed  of  concentric  layers  of  fibrous  matter  decussating  each 
other,  and  having  intervals  between  them,  which  are  more  considerable  to- 
wards the  centre.  These  intervals  are  filled  by  a soft  elastic  pulpy  tissue, 
which  is  gradually  increased  in  quantity  towards  the  centre. 

The  articulating  processes  of  the  vertebree  are  connected  by  synovial  mem- 
branes, and  by  ligamentous  fibres  extended  irregularly  between  them. 

Between  the  back  part  of  the  plates  of  the  vertebrae  are  the  ligamenta  sub- 
flava.  These  ligaments  close  the  intervals  between  the  vertebrae,  and  thus 
complete  the  back  part  of  the  spinal  canal.  They  exist  between  all  the  ver- 
tebrae, from  the  second  to  the  sacrum;  they  are  composed  of  dense,  yellow, 
elastic  fibres,  united  angularly  to  each  other  towards  the  base  of  each  spinous 
process. 

The  spinous  processes  of  the  vertebrae  are  also  connected  to  each  other  by 
ligamentous  bands,  termed  sapra-spinous,  and  biter -spinous  (the  ligamenta 
sub-fiava  might  be  called  infra-spinous).  Between  the  transverse  processes 
also  ligamentous  fibres  exist  which  are  named  inter-transverse  ligaments. 

ARTICULATIONS  OF  THE  RIBS. 

The  head  of  each  rib  is  joined  to  the  spine  by  an  anterior  and  an  inter- 
articular  ligament,  and  by  synovial  membrane;  the  anterior  ligament,  arises 
from  the  front  of  the  head  of  the  rib,  and  thence  extends  over  the  articulation 
in  a radiated  manner,  and  is  inserted  into  the  side  of  the  vertebra  above  and 
below,  and  into  the  inter-vertebral  substance.  The  inter-articular  ligament, 
arises  from  the  projecting  ridge  in  the  articular  surface  of  the  rib,  and  is 
inserted  into  the  cavity  in  the  inter-vertebral  substance  in  which  the  head  is 
received.  The  upper  and  lower  divisions  of  this  joint  as-e  lined  by  distinct 
synovial  membranes. 

The  tubercle  of  each  rib  is  united  to  the  transverse  process  of  the  inferior 


240 


THE  DUBLIN  DISSECTOR, 


of  the  two  vertebrae,  to  the  bodies  of  which  the  head  is  attached  by  three  liga- 
ments and  a synovial  membrane.  First,  the  inferior  costo-transverse  ascends 
from  the  neck  of  each  rib  obliquely  outwards  to  the  transverse  process  above ; 
second  and  third,  the  posterior  and  external  costo-transverse  connect  the 
tubercle  of  each  rib  to  the  corresponding  transverse  process.  The  synovial 
membranes  covering  the  cartilaginous  surfaces  of  the  transverse  processes 
and  tubercles  of  the  ribs,  are  more  loose  than  those  belonging  to  the  heads  of 
the  ribs. 

The  cartilages  of  the  ribs  at  their  costal  ends  are  convex,  and  are  very 
closely  united  to  the  concave  surfaces  in  the  extremities  of  the  bones.  The 
sternal  ends  of  the  cartilages  of  the  seven  true  ribs  are  convex,  adapted  to 
the  hollows  in  the  edge  of  the  sternum;  these  hollows  are  covered  by  carti- 
lage and  by  synovial  membranes ; each  joint  is  strengthened  by  ligamentous 
bands,  which  proceed  from  the  cartilage  before  and  behind  the  articulation, 
and  are  expanded  upon  the  sternum.  There  is  no  distinct  joint  between  the 
first  rib  and  the  sternum,  the  cartilage  and  bone  appear  to  be  continuous. 

ARTICULATIONS  OF  THE  PELVIS. 

The  last  lumbar  vertebra  is  joined  to  the  sacrum  in  the  same  manner  as  the 
other  vertebrae  are  to  each  other.  The  last  lumbar  vertebra  is  connected  to 
the  ilium  by  the  ilio-lumbar  ligament ; this  is  sometimes  divided  into  two,  it 
arises  from  the  transverse  processes  of  the  fifth  and  fourth  lumbar  vertebrae, 
and  from  the  back  part  of  the  sacrum,  proceeds  horizontally  outwards,  and  is 
inserted  into  the  posterior  superior  spinous  process  and  crest  of  the  ilium. 
The  ilium  and  sacrum  are  firmly  united  by  a cartilage  which  consists  of  two 
layers,  one  adhering  to  each  bone  ; behind  this  they  are  connected  by  short 
ligamentous  fibres,  also  by  the  sacro-sciatic  ligaments,  which  are  two  in  num- 
ber on  each  side,  1st,  the  posterior  or  great  sacro-seiatic  ligament,  arises  from 
the  lower  and  back  part  of  the  posterior  inferior  spine  of  the  ilium,  and  from 
the  back  part  of  the  sacrum  and  coccyx ; descends  obliquely  outwards,  be- 
comes narrow  and  thick,  and  is  inserted  into  the  lower  edge  of  the  tuber  ischii ; 
2d,  the  anterior  or  lesser  sacro  sciatic  ligament,  triangular,  arises  from  the 
side  of  the  sacrum  and  coccyx,  passes  outwards,  and  is  inserted  into  the  spine 
of  the  ischium.  The  coccyx  is  united  to  the  sacrum  by  a substance  resem- 
bling the  inter-vertebral,  also  by  ligamentous  bands  before  and  behind.  The 
ossa  pubis  are  closely  attached  by  several  laminae  of  fibro-cartilage ; poste- 
riorly a little  fluid  separates  these  bones  which  are  each  covered  by  cartilage: 
this  connection  is  strengthened  interiorly  by  the  pubic  ligament,  which  is  very 
dense,  and  passes  from  the  ramus  of  one  bone  to  the  opposite.  The  obturator 
ligament  is  a thin  fascia  adhering  to  the  margin  of  the  obturator  hole,  except 
superiorly,  where  the  thyroid  nerve  and  vessels  pass  through. 

STERNO-CLAVICULAR  ARTICULATION. 

The  clavicle  is  connected  to  the  sternum  by  an  anterior,  posterior,  inferior, 
and  inter-clavicular  ligament,  also  by  an  inter-articular  cartilage  and  two 
synovial  membranes;  the  anterior  ligament  arises  from  the  end  of  the  cla- 
vicle, descends  inwards,  and  is  inserted  into  the  fore-part  of  the  sternum; 


OR  MANUAL  OF  ANATOMY. 


241 


the  posterio r ligaments  takes  a course  parallel  to  the  preceding,  behind  the 
joint;  the  inferior  or  the  costo- clavicular  or  rhomboid  ligaments,  passes 
from  the  lower  surface  of  the  sternal  end  of  the  clavicle,  and  is  inserted  into 
the  cartilage  of  the  first  rib ; the  inter-clavicular  extends  from  the  posterior 
surface  of  one  clavicle  to  the  other,  the  cervical  fascia  is  attached  to  the  upper 
edge  of  this  ligament;  the  inter -articular  cartilage  is  thin  below,  and 
attached  to  the  sternum,  thick  above  and  attached  to  the  clavicle;  a synovial 
membrane  is  connected  to  each  surface  of  this  cartilage. 

SCAPULO-CLAVICULAR  ARTICULATION. 

The  oval  end  of  the  clavicle  is  connected  to  the  end  of  the  acromion  pro- 
cess by  a superior  and  inferior  ligament,  which  are  attached  to  the  sur- 
faces of  each  bone,  there  is  also  a synovial  membrane  between  both;  some- 
times there  is  an  inter-articular  cartilage  in  this  articulation;  about  an  inch 
internal  to  this  joint  the  clavicle  is  connected  to  the  coracoid  process  by  two 
fasciculi  of  ligamentous  fibres,  which  do  not  properly  belong  to  this  articula- 
tion, they  are  the  conoid  and  trapezoid  ligaments. 

The  conoid  is  the  smaller  of  the  two,  its  base  is  attached  to  a tubercle  on 
the  lower  surface  of  the  clavicle,  its  apex  to  the  broad  part  of  the  coracoid 
process.  The  trapezoid  is  more  anterior  and  external,  it  is  also  broader  and 
stronger  than  the  conoid,  it  is  about  an  inch  distant  from  the  articulation,  it  is 
attached  above  to  an  oblicpie  line  on  the  clavicle,  and  below  to  the  upper  part 
of  the  coracoid  process  ; these  ligaments  are  united  posteriorly  and  externally, 
anteriorly  they  are  distinct. 

LIGAMENTS  OF  THE  SCAPULA. 

These  are  two  in  number,  an  anterior  and  posterior. 

The  anterior,  or  the  deltoid  or  coraco-acromial,  arises  broad  from  the  caro- 
coid  process,  passes  upwards  and  outwards,  and  is  inserted  narrow  into  the 
point  of  the  acromion  process.  The  posterior  or  coracoid  ligament  arises 
from  the  costa  of  the  scapula  behind  the  notch,  passes  forwards,  and  is  inserted 
into  the  base  of  the  coracoid  process;  it  converts  the  notch  into  a foramen: 
this  ligament  is  sometimes  wanting,  then  the  notch  is  completed  into  a hole  by 
bone  : the  supra-scapular  nerve  usually  passes  below  this  ligament,  while  the 
vessels  of  this  name  run  above  it. 

HUMERO-SCAPULAR  ARTICULATION. 

The  head  of  the  humerus  is  retained  in  the  glenoid  cavity  by  the  capsular 
and  coraco-humeral  ligaments,  and  by  a synovial  membrane ; the  glenoid 
cavity  is  deepened  by  a fibrous  border,  which  is  partly  derived  from  the 
tendon  of  the  biceps. 

The  capsular  ligament  arises  around  the  neck  of  the  scapula,  increases  in 
size,  encircles  the  head  of  the  humerus,  and  is  inserted  into  its  neck ; it  is 
dense  above  and  below,  thin  internally  and  externally;  this  capsule  is  very 
loose  and  long,  the  tendons  of  the  capsular  muscles  are  identified  with  it. 

The  coraco-humeral  ligament  extends  from  the  coracoid  process  to  the 
SI 


242 


THE  DUBLIN  DISSECTOR, 


anterior  part  of  the  great  tuberosity,  where  it  becomes  confounded  with  the 
capsule  and  with  the  tendon  of  the  supra-spinatus.  The  synovial  membrane 
is  reflected  over  the  glenoid  surface  around  the  glenoid  ligament,  lines  the 
capsule,  and  covers  the  head  of  the  humerus,  and  also  lines  the  bicipital 
groove. 

HUMERO- CUBITAL  ARTICULATION,  OR  THE  ELBOW-JOINT. 

The  opposed  extremities  of  the  humerus,  ulna,  and  radius,  mutually  receive 
each  other,  and  are  attached  together  by  an  external  and  internal  lateral,  and 
by  an  anterior  and  posterior  ligament. 

The  external  lateral  ligament  arises  from  the  external  condyle,  and  is  in- 
serted into  the  annular  ligament  of  the  radius;  this  ligament  is  confounded 
with  the  tendons  of  the  supinator  and  extensor  muscles. 

The  internal  lateral  arises  from  the  inner  condyle,  and  is  inserted  in  a 
radiated  manner  into  the  inner  edge  of  the  coronoid  and  olecranon  processes, 
it  is  longer  and  broader  than  the  external,  is  somewhat  triangular,  and  divides 
interiorly  into  two  fasciculi,  the  anterior  of  which  extends  to  the  coronoid  pro- 
cess, and  is  confounded  with  the  common  tendinous  origin  of  the  muscles  of 
the  fore-arm ; the  posterior  is  inserted  into  the  olecranon  process,  is  covered 
by  the  ulnar  nerve  and  connected  to  the  adjacent  muscles;  both  portions 
adhere  to  the  synovial  membrane. 

The  anterior  ligament  consists  of  thin  fibres  which  take  an  irregular  direc- 
tion over  the  fore-part  of  the  joint;  they  arise  chiefly  from  above  the  internal 
condyle,  and  the  depression  on  the  fore-part  of  the  humerus ; they  thence 
spread  over  the  synovial  membrane,  behind  the  brachiaeus  anticus  ; some  arc 
inserted  into  the  annular  ligament  of  the  radius,  and  the  remainder  are 
gradually  lost  on  the  synovial  membrane. 

The  posterior  ligament  is  not  so  distinct  as  the  anterior,  unless  the  fore- 
arm be  flexed;  the  fibres  chiefly  extend  in  a transverse  direction  from  one 
condyle  to  the  other,  they  are  attached  to  the  synovial  membrane,  and  covered 
by  the  triceps  and  anconseus. 

The  synovial  membrane  is  common  to  the  humero-cubita!  as  well  as  to  the 
cubito-radial  articulation;  this  membrane  descends  behind  the  anterior  liga- 
ment, and  a quantity  of  reddish  fatty  matter  which  intervenes,  to  the  neck  of 
the  radius  and  annular  ligament;  round  which  it  forms  a cul  de  sac,  is  pro- 
longed into  the  sigmoid  cavities  of  the  ulna,  and  thence  is  reflected  to  the  lateral 
ligaments  and  to  the  triceps  tendon,  which  leads  it  to  the  posterior  depression 
on  the  humerus,  it  is  thence  expanded  over  the  articular  eminences  at  the 
lower  end  of  this  bone. 

RADIO-ULNAR  ARTICULATIONS. 

These  are  two,  a superior  and  an  inferior  ; in  the  superior  the  head  of  the 
radius  is  received  into  the  lesser  sigmoid  cavity  of  the  ulna,  and  is  retained 
in  it  by  the  following  ligament.  The  annular  ligament  forms  about  three- 
fourths  of  a circle ; it  arises  from  the  anterior,  and  is  inserted  into  the  poste- 
rior border  of  the  lesser  sigmoid  cavity  of  the  ulna;  this  ligament  is  lined  by 
the  synovial  membrane  of  the  joint,  it  encircles  the  head  and  neck  of  the 
radius;  it  often  presents  a cartilaginous  structure, 


OR  MANUAL  OF  ANATOMY. 


243 


The  oblique  ligament  is  a small  round  fibrous  cord,  it  arises  from  the  coro- 
noid  process  of  the  ulna,  descends  obliquely  outwards,  and  is  inserted  into 
the  radius  below  its  tubercle;  it  is  on  a plane  anterior  to  the  inter-osseous 
ligament,  and  it  separates  the  flexor  digitorum  sublimis  from  the  supinator 
radii  brevis  muscle. 

The  opposed  edges  of  the  radius  and  ulna  are  connected  by  a thin  aponeu- 
rosis the  inter -osseal  membrane  or  ligament ; it  is  composed  of  long  fibres 
which  descend  obliquely  inwards  from  the  radius  to  the  ulna;  this  ligament 
is  deficient  above  and  below,  and  in  many  places  is  perforated  by  vessels. 

In  the  inferior  radio-ulnar  articulation,  the  round  head  of  the  ulna  is 
received  into  the  sigmoid  cavity  of  the  radius,  and  retained  in  it  by  a loose 
synovial  membrane  or  the  sacciform  ligament,  which  is  covered  before  and 
behind  by  some  ligamentous  fibres ; it  passes  from  the  radius  to  the  ulna,  and 
forms  a very  loose  sac  above  the  following  ligament  or  cartilage ; it  always 
contains  a quantity  of  synovia. 

The  fibro  cartilage  is  triangular,  it  arises  narrow  from  the  styloid  process 
of  the  ulna,  and  is  inserted  broad  into  the  inner  edge  of  the  radius  below  the 
ulna,  which  bone  it  separates  from  the  wrist  joint,  or  from  the  cuneiform  bone, 
its  anterior  and  posterior  edges  are  connected  to  the  ligamentous  fibres  that 
pass  from  the  ulna  to  the  radius. 

RADIO-CARPAL  ARTICULATION,  OR  THE  WRIST  JOINT.  v 

In  this  joint  the  lower  end  of  the  radius  and  the  inter-articular  cartilage 
form  a socket  for  the  scaphoid,  lunar,  and  cuneiform  bones  ; this  joint  is 
secured  by  an  external  and  internal  lateral,  and  by  a posterior  and  anterior 
ligament. 

The  external  lateral  extends  from  the  styloid  process  of  the  radius  and  is 
inserted  into  the  scaphoid  bone ; some  fibres  extend  to  the  annular  ligament 
and  to  the  os  trapezium. 

The  internal  lateral  extends  obliquely  downwards  and  forwards,  from  the 
styloid  process  of  the  ulna  to  the  cuneiform  bone. 

The  anterior  and  posterior  ligaments  descend  from  the  radius  and  inter- 
articular  cartilage  anteriorly  and  posteriorly,  and  are  inserted  into  the  supe- 
rior row  of  the  carpus.  A synovial  membrane  covers  the  superior  rour  of  the 
carpal  bones,  is  thence  reflected  to  line  the  ligaments,  and  is  continued  over 
the  articular  surface  of  the  radius,  and  of  the  inter-articular  cartilage. 

The  three  first  bones  of  the  carpus  are  connected  to  each  other  by  liga- 
mentous bands,  both  on  the  dorsal  and  palmar  aspects,  passing  in  different 
directions  from  one  bone  to  another;  the  pisiform  is  articulated  distinctly  to 
the  cuneiform  bone  : the  bones  of  the  second  row  are  connected  to  each  other 
in  the  same  manner  as  those  of  the  first,  and  the  two  rows  are  attached  by  two 
lateral  ligaments  and  by  dorsal  and  palmar  bands,  also  by  the  head  of  the  os 
magnum  being  received  into  the  cavity  formed  by  the  lunar  and  scaphoid 
bones;  one  synovial  membrane  extends  between  these  two  rows,  and  sends 
processes  between  the  individual  bones,  the  bones  of  the  carpus  are  also 
firmly  connected  to  each  other  by  the  annular  ligament,  which  is  inserted 
externally  into  the  trapezium  and  scaphoid,  internally  into  the  cuneiform  and 
unciform  bones. 


244 


THE  DUBLIN  DISSECTOR, 


The  articulations  between  the  carpus  and  metacarpus  are  secured  by  trans- 
verse and  oblique  fibrous  bands,  which  cover  the  synovial  membranes,  and  pass 
in  different  directions ; the  articulations  between  the  heads  of  the  metacarpal 
bones  and  the  first  phalanges  are  furnished  with  very  loose  synovial  mem- 
branes and  lateral  ligaments ; the  phalanges  of  the  fingers  are  articulated  to 
each  other  by  synovial  membranes  and  lateral  ligaments. 

ILIO-FEMORAL  ARTICULATION,  OR  HIP  JOINT. 

The  head  of  the  femur  is  received  into  the  acetabulum,  which  cavity  is 
deepened  by  the  cotyloid  ligament,  which  is  a circular  fibrous  band  adhering 
to  the  edge  of  the  bony  cup,  and  lined  by  synovial  membrane : the  notch  at 
the  inner  part  of  the  cavity  is  partly  closed  by  the  transverse  ligament,  which 
is  attached  to  the  opposite  points  of  the  pubis  and  ischium. 

The  capsule  of  this  joint  is  the  strongest  in  the  body.  It  consists,  like  the 
capsule  of  the  shoulder  joint,  of  a fibrous  and  a synovial  membrane.  The 
fibrous  membrane  is  attached  above  to  the  circumference  of  the  acetabulum  ; 
and  below  to  the  root  of  the  trochanter  major,  and  to  the  two  oblique  inter- 
trochanteric lines  ; it  is  very  strong  externally  and  anteriorly,  thin  internally. 
The  synovial  membrane  is  reflected  from  the  inside  of  the  fibrous  membrane 
upon  the  periosteum  of  the  neck,  and  upon  the  cartiliginous  surface  of  the 
head  of  the  femur ; from  the  latter  it  is  reflected  around  the  inter-articular 
ligament,  and  is  then  continued  to  the  cartilaginous  surface  of  the  acetabulum. 
The  attachment  of  the  fibrous  layer  extends  upon  the  femur,  a little  wav 
beyond  the  synovial  membrane,  especially  at  the  outer  and  posterior  part  of 
the  joint. 

The  accessory  or  ilio  femoral  ligament  extends  from  the  inferior  spinous 
process  of  the  ilium  obliquely  downwards  and  inwards,  adhering  to  the  fore- 
part of  the  capsule,  and  is  inserted  into  the  fore-part  of  the  lesser  trochanter. 

The  inter-articular  ligament,  or  ligamentuni  teres,  arises  narrow  from  the 
depression  on  the  head  of  the  femur,  passes  downwards  and  inwards,  and  be- 
coming broad,  is  inserted  by  two  fibrous  bands  into  the  extremities  of  the 
notch  in  the  edge  of  the  acetabulum,  and  by  the  synovial  membrane  to  the 
fatty  substance  that  covers  the  rough  surface  at  the  bottom  of  the  cavity. 

FEMORO  -TIBI AL  ARTICULATION,  OR  THE  KNEE  JOINT. 

The  condyles  of  the  femur,  the  head  of  the  tibia,  and  the  patella,  enter 
into  this'  articulation;  the  ligaments  which  secure  it  may  be  classed  into  those 
external  and  those  internal  to  the  synovial  membrane,  although  strictly  they 
are  all  external  to  it ; the  external  ligaments  are,  the  ligamentum  patellae,  liga- 
menturn  posticum,  and  the  internal  and  external  lateral  ligaments. 

The  ligamentum  patellae  consists  of  strong1  parallel  tendinous  fibres  which 
descend  from  the  inferior  angle  of  the  patella,  and  are  inserted  into  the  tuber- 
cle of  the  tibia,  a little  below  a small  bursa  which  lies  behind  this  ligament; 
it  is  partly  a continuation  of  the  extensor  tendon. 

The  posterior  ligament  has  been  noticed  in  the  dissection  of  the  semi- 


OR  MANUAL  OF  ANATOMY. 


245 


membranosus  muscle,  from  the  tendon  of  which  this  ligament  arises-,  it  then 
ascends  obliquely  from  behind  the  inner  condyle  of  the  tibia  to  the  external 
condyle  of  the  femur. 

The  internal  lateral  ligament  is  broad  and  flat,  arises  from  the  internal 
condyle  of  the  femur,  descends  obliquely  forwards,  and  is  inserted  into  the 
internal  condyle  of  the  tibia,  and  into  the  semilunar  cartilage. 

The  external  lateral  ligament  or  ligaments  arise  from  the  external 
condyle,  are  thick  and  round,  descend  backwards,  and  are  inserted  into  the 
head  of  the  fibula : a portion  of  the  biceps  tendon  sometimes  separates  these 
ligaments;  in  many  cases  they  form  but  a single  cord. 

The  synovial  membrane  of  the  knee  is  the  largest  in  the  body;  it  ascends 
between  two  and  three  inches  on  the  fore-part  of  the  femur,  is  thence  reflected 
to  the  patella,  and  to  the  adjoining  muscles  or  tendons  and  is  continued  down 
to  the  head  of  the  tibia ; it  is  thence  reflected  round  the  inter-articular  carti- 
lages, and  along  the  crucial  ligaments  to  the  femur. 

The  internal  ligaments  in  this  joint  are,  the  alar,  mucous,  transverse, 
crucial,  and  the  semilunar  cartilages. 

The  alar  ligaments  are  folds  of  the  synovial  membrane,  one  on  either 
side  of  the  patella  and  united  below  that  bone. 

The  ligamenium  mucosum  is  a small  fold  of  the  same  membrane,  passing 
from  the  fatty  substance  behind  the  iigamentum  patellae,  backwards  and  up- 
wards to  the  hollow  between  the  condyles. 

The  transverse  ligament  extends  between  the  anterior  convex  portions  of 
the  two  semilunar  cartilages,  and  above  the  fatty  substance  before  alluded  to. 

The  anterior  crucial  ligament  arises  from  the  inner  side  of  the  external 
condyle,  descends  obliquely  forwards,  and  is  inserted  near  the  fore-part  of  the 
head  of  the  tibia. 

The  posterior  crucial  ligament  arises  from  the  outer  side  of  the  internal 
condyle,  descends  nearly  vertical,  and  is  inserted  partly  into  the  external  semi- 
lunar cartilage,  and  partly  into  the  depression  on  the  back  of  the  tibia. 

The  semilunar  cartilages  are  placed  upon  the  articular  surfaces  of  the  tibia ; 
the  convex  margin  of  each  is  thick  ; the  internal  concave  margin  has  a sharp 
edge ; each  cartilage  presents  above  an  excavated  surface,  adapted  to  the  con- 
dyles, and  below,  a flat  surface,  adapted  to  the  head  of  the  tibia;  externally 
they  are  connected  with  the  lateral  ligaments,  while  their  internal  edges  are 
loose  in  the  cavity  of  the  joint.  The  anterior  and  posterior  extremities  of  each 
are  fixed  to  the  head  of  the  tibia,  before  and  behind  its  middle  protuberance. 

The  two  cartilages  are  united  in  front  by  the  transverse  ligament;  the  ex- 
ternal cartilage  is  circular  and  more  movable  than  the  internal,  which  is  of  an 
oval  figure. 

The  head  of  the  fibula  is  connected  to  the  small  smooth  surface  on  the  outer 
side  of  the  head  of  the  tibia,  by  a synovial  membrane,  and  by  an  anterior 
and  posterior  fasciculus  of  ligamentous  fibres. 

The  bodies  of  these  two  bones  are  connected  by  the  inter-osseous  membrane, 
which  consists  of  aponeurotic  fibres  extending  obliquely  from  one  bone  to  the 
other ; they  are  deficient  above  and  below.  The  inferior  extremity  of  the 
fibula  is  received  into  a depression  in  the  tibia,  and  connected  to  it  by  a strong 
anterior  and  posterior  ligament,  which  are,  each,  of  a triangular  form,  the  base 


£46 


THE  DUBLIN  DISSECTOR. 


below;  also  by  a synovial  membrane,  and  an  intervening  dense,  fibrous  sub- 
stance : some  fibres  of  the  posterior  ligament  extend  from  one  malleolus  to 
the  other  and  strengthen  the  ankle  joint. 

ARTICULATION  OF  THE  ANKLE. 

The  astragalus  is  received  into  a cavity  formed  in  the  tibia  and  fibula,  and 
secured  in  it  by  very  strong  lateral  ligaments,  and  also  by  a synovial  mem- 
brane and  an  anterior  ligament. 

The  internal  lateral  or  deltoid  ligament  is  verv  dense  it  arises  from  the 
internal  malleolus,  deccnds  in  a radiated  manner,  and  is  inserted  into  the 
astragalus,  os  naviculare  and  calcis. 

The  external  lateral  ligaments  are  three,  a posterior,  middle,  and  anterior ; 
they  all  arise  from  the  external  malleolus;  the  posterior  passes  obliquely  in- 
wards to  the  ridge  on  the  back  of  the  astragalus  between  the  ankle  and  the  ar- 
ticulation of  the  astragalus  to  the  os  calcis;  the  middle  descends  vertically  and 
is  inserted  into  the  os  calcis  the  anterior  is  inserted  into  upper  and  outer  part  of 
the  astragalus.  The  anterior  ligament  of  the  ankle  is  often  indistinct ; it  arises 
from  the  anterior  edge  of  the  tibia,  and  is  inserted  into  the  upper  and  outer  part 
of  the  astragalus.  The  knee,  elbow,  and  ankle  joints,  unlike  those  of  the  hip 
and  shoulder,  have  no  proper  fibrous  capsular  ligament,  independent  of  the 
synovial  membrane. 

Articulation  of  the  Tarsus.  The  astragalus  is  attached  to  the  os  calcis 
by  two  articulating  surfaces,  each  of  which  is  furnished  with  a synovial  mem- 
brane ; between  these  is  a dense  inter-osseous  ligament ; there  is  also  & poste- 
rior ligament,  which  is  attached  to  the  adjoining  surfaces  of  the  two  bones; 
the  head  of  the  astragalus  is  articulated  to  the  navicular  bone,  the  end  of  the 
os  calcis  is  also  connected  to  the  latter  by  a strong  fibro  cartilaginous  substance 
called  calceo  navicular  ligament;  this  extends  from  the  inferior  surface  of 
the  os  calcis  to  the  inferior  part  of  the  navicular,  though  not  attached  to  the 
astragalus,  it  supports  it,  and  completes  the  cavity  for  receiving  its  head;  this 
ligament  is  strengthened  by  the  tendon  of  the  tibialis  posticus,  which  in  this 
situation  frequently  contains  a sesamoid  bone  or  cartilage.  A thin  broad  liga- 
ment above  also  connects  the  astragalus  to  the  navicular.  The  os  calcis  is  at- 
tached to  the  cuboid  by  a synovial  membrane  and  superior  and  inferior  liga- 
ments ; the  latter  is  very  strong,  radiated  anteriorly,  and  attached  to  the  third 
and  fourth  metatarsal  bones.  This  articulation  is  exactly  opposite  to  that  be- 
tween the  astragalus  and  navicular  bone  ; the  opposite  sides  of  the  cuboid  and 
navculiar  bones  are  connected  by  ligaments  and  sometimes  by  synovial  mem- 
brane. The  three  cuneiform  bones  are  attached  to  the  navicular  by  a synovial 
membrane  which  also  extends  between  these ; they  are  all  secured  by  superior 
and  inferior  transverse  and  oblique  ligamentous  bands.  The  metatarsal  bones 
are  secured  to  the  tarsus  and  to  each  other  by  dorsal  and  plantar  ligaments  : 
the  three  internal  are  articulated  to  the  cuneiform  bones,  and  the  two  exter- 
nal to  the  cuboid  bones;  all  the  metatarsal  bones  are  also  articulated  to  each 
other  posteriorly  by  synovial  membranes,  except  the  first  and  second  ; the 
anterior  end  of  each  metatarsal  bone  is  connected  to  the  first  phalanx,  and  the 
phalanges  to  each  other  by  synovial  membranes  and  lateral  ligaments  a?  in  tire 
upper  extremity. 


PART  V. 


DESCRIPTION  OF  THE  BONES. 

The  osseous  structure  is  the  hardest  in  the  body  ; it  is  composed  chiefly 
of  phosphate  of  lime,  Avith  a little  carbonate  deposited  in  a cartilaginous 
substance  which  is  perfectly  organized  and  well  supplied  with  vessels  for  its 
nourishment  and  growth.  The  bones  present  great  variety  of  figure;  they 
are  commonly  classed  into  the  flat,  long , and  irregular.  They  support  and 
protect  the  soft  parts,  give  the  general  form  to  the  whole  body  as  well  as 
to  its  different  parts,  they  also  serve  as  the  passive  organs  of  locomotion, 
affording  a series  of  levers  by  means  of  which  the  muscles  effect  the  various 
motions  and  actions  of  the  body. 

When  all  the  bones  are  connected  by  their  ligaments,  the  collection  is 
called  a natural  skeleton ; when  united  by  art,  an  artificial  skeleton.  The 
skeleton  is  divided  into  the  ti'unk  and  extremities. 

The  trunk  consists  of  the  middle  part  and  two  extremities;  the  middle  of 
the  trunk  is  formed  by  the  vertebral  column  and  the  chest;  the  upper  extre- 
mity of  the  trunk  is  the  head,  the  lower  the  pelvis. 

The  vertebral  column  consists  of  twenty-four  vertebrae,  which  are  divided 
into  three  classes  according  to  the  three  regions,  viz.  seven  cervical,  twelve 
dorsal,  and  five  lumbar. 

The  chest  or  thorax  is  formed  before  by  the  sternum,  which  consists  of  two 
or  three  pieces,  on  either  side  by  the  twelve  ribs,  and  behind  by  the  dorsal 
vertebrae. 

The  head  comprises  the  cranium  and  the  face:  the  cranilon  or  skull,  is 
composed  of  the  frontal,  the  two  temporal,  two  parietal,  the  occipital,  the 
ethmoid  and  the  sphenoid  bones  ; to  these  may  be  added  the  small  turbinated 
bones  of  the  sphenoid  or  of  Bertin,  and  the  four  auricular  bones  in  each  tem- 
poral bone,  which  have  been  already  described  in  the  anatomy  of  the  ear. 

The  face  is  divided  into  the  upper  and  lower  jaw;  the  upper  consists  of 
the  two  superior  maxillary,  two  palatine,  two  lachrymal,  two  nasal,  two  malar, 
two  inferior  turbinated  bones  and  the  vomer;  to  these  may  be  added  the 
sixteen  teeth.  The  lower  jaw  consists  of  the  inferior  maxillary  bone, 
which  contains  sixteen  teeth  ; some  consider  the  os  hyoides  as  an  appendix  to 
the  bones  of  the  face;  this  bone  however  has  been  already  noticed  in  the 
description  of  the  lafynx. 

The  pelvis  is  the  lower  extremity  of  the  trunk ; it  consists  of  the  sacrum, 
the  coccyx,  and  the  two  ossa  innominata. 

The  superior  or  thordccic  extremities  are  composed  each  of  four  parts,  the 
shoulder,  which  consists  of  the  clavicle  and  scapula ; the  arm,  of  the  humerus ; 
the  fore-arm  of  the  radius  and  ulna;  and  the  hand,  which  is  subdivided  into 
the  carpus,  matacarpus,  and  fingers.  The  carpus  consists  of  eight  small 

247 


248 


THE  DUBLIN  DISSECTOR, 


bones ; the  metacarpus  of  five,  and  the  fingers  each  of  three  phalanges  except 
the  thumb,  which  has  only  two. 

The  inferior  or  abdominal  extremities  are  each  divided  into  three  parts ; 
the  thigh,  which  consists  of  but  one  bone,  the  femur;  the  leg,  which  consists 
of  three,  the  patella,  tibia,  and  fibula;  and  the  foot,  which  is  divided  into 
three  parts,  the  tarsus,  metatarsus,  and  toes;  the  tarsus  consists  of  seven 
irregular  bones,  the  metatarsus  of  five  long  bones,  and  the  toes  of  the  three 
phalanges  each,  except  the  great  toe,  which  has  only  two.  In  the  adult 
skeleton  the  number  of  bones  amount  to  242,  including  the  bones  of  the  ear 
and  the  teeth,  but  excluding  the  os  hyoides  and  the  sesamoid  bones. 

THE  VEUTEBPJE. 

The  Vertebrae  are  twenty -four  in  number,  they  belong  to  the  class  of  irre- 
gular bones,  are  placed  one  above  the  other,  and  connected  by  ligaments  so  as 
to  form  one  solid,  yet  flexible  column,  placed  in  the  middle  and  back  part  of 
the  trunk,  and  extending  from  the  head  to  the  sacrum.  All  the  vertebrae 
agree  in  the  general  outline,  which  is  as  follows  ; each  vertebra  consists  of  a 
body  and  of  several  projections  or  processes  : the  body  occupies  the  anterior 
central  part;  it  is  thick  and  spongy,  and  rather  circular  or  oval;  its  flat 
surfaces  above  and  below  give  attachment  to  the  intervertebral  ligaments ; 
the  margin  of  each  is  tipped  with  a compact  white  substance  ; anteriorly  it  is 
transversely  convex  and  very  porous,  posteriorly  concave,  so  as  to  form  part 
of  the  spinal  canal  of  foramen  ; this  surface  is  perforated  by  several  holes  for 
vessels.  The  processes  of  each  vertebra  arc  nine,  two  lateral  or  the  laminae, 
two  transverse,  four  oblique  or  articulating,  and  one  spinous. 

The  lateral  processes  or  laminae,  arise,  one  on  each  side  by  a sort  of  pedicle 
from  the  posterior  part  of  the  body;  they  pass  backwards,  bounding  the  sides 
of  the  spinal  hole,  and  unite  posteriorly  in  the  spinous  process ; they  are 
broad  behind,  but  narrow  where  they  join  the  body,  being  grooved  out  above 
and  below  into  a notch;  the  inferior  of  these  is  the  larger;  these  notches, 
when  the  vertebrae  are  joined,  form  the  intervertebral  holes  for  the  passage  of 
the  spinal  nerves.  The  spinous  process  is  the  most  projecting  part  of  the 
vertebra  in  the  posterior  median  line ; its  base  is  bifurcated,  its  apex  generally 
ends  in  a point  or  tubercle.  The  tranverse  processes  arise  from  the  laminae, 
and  are  directed  outwards  on  each  side.  The  articular  or  oblique  processes 
arise  from  the  roots  of  the  transverse,  two  ascend,  two  descend ; they  arc 
covered  with  cartilage,  and  articulate  with  the  corresponding  processes 
of  the  vertebra  above  and  below.  The  spinal  hole  or  canal  is  bounded 
by  the  body  and  processes ; it  is  oval  or  triangular.  The  processes  of 
the  vertebrae  are  of  a more  compact  structure  than  the  bodies,  which  are 
very  light  and  spongy.  A vertebra  is  generally  developed  by  three  points 
of  bone,  one  for  the  body,  and  one  on  each  side  for  the  laminae  and  articulating 
processes;  sometimes  a fourth  point  is  deposited  for  the  spinous;  this  process 
is  seldom  found  ossified  in  the  foetus,  but  remains  cartilaginous  for  some  time. 
In  addition  to  these  three  principal  ossific  points,  there  are  frequently  acces- 
sary points  or  epiphyses  found  in  the  processes,  as  well  as  on  the  surfaces  of 
the  body.  These  are  the  general  characters  of  all  the  vertebrae,  but  each  of 
he  three  classes  present  some  peculiarity. 


OR  MANUAL  OF  ANATOMY. 


249 


The  lumbar  vertebrx  are  five  ; these  are  the  largest  in  the  column  ; the  body 
of  each  is  very  broad  transversely,  compared  with  its  height;  its  upper  and 
lower  surfaces  are  flat,  and  bordered  with  hard  projecting  edges,  which  render 
it  concave  from  above  downwards  on  its  fore-part.  The  laminae  are  thick, 
broad,  but  short;  the  notches , particularly  the  lower,  are  very  large;  the 
spinous  process  is  broad,  flat,  and  square,  and  ends  not  in  a point,  but 
in  a thick,  rough  border;  the  articulating  processes  are  oval,  strong,  and 
vertical : the  superior  are  concave  and  look  inwards ; the  inferior  are 
convex  and  look  outwards  ; the  transverse  processes  are  long,  thin,  and  hori- 
zontal, and  more  anterior  than  those  of  the  dorsal  vertebrae ; the  spinal 
foramen  is  triangular,  and  larger  than  in  the  back  ; the  body  of  the  5th 
lumbar  vertebra  is  cut  off  obliquely  below,  so  as  to  be  much  thicker  before 
than  behind  ; its  transverse  processes  are  short,  strong,  and  rounded. 

The  dorsal  vertebrx  are  twelve  in  number,  and  of  an  intermediate  size 
between  the  cervical  and  lumbar;  they  decrease  from  the  1st  to  the  4th,  and 
then  increase  to  the  last,  so  that  the  4th  and  5th  are  the  smallest.  The  body 
is  thicker  behind  than  before,  and  longer  from  before  backwards  than  trans- 
versely, flap  above  and  below  and  round,  except  in  the  1st,  whose  surfaces 
are  heart  shaped,  and  very  convex  anteriorly;  on  either  side  it  presents  two 
small  depressions  or  notches,  covered  with  cartilage;  the  superior  is  the 
larger ; when  the  vertebra  are  conjoined  two  of  these  notches  form  an  oval 
depression  for  the  head  of  each  rib ; the  laminae  are  broad  and  thick  ; the 
notches  are  large  and  anterior  to  the  oblique  processes  ; the  transverse  pro- 
cesses are  long  and  large,  and  directed  backwards : on  the  front  of  each  near 
the  end  except  of  the  last  two,  there  is  a small  depression  covered  with  carti- 
lage for  articulating  with  the  tubercle  of  the  rib ; the  oblique  processes  are 
vertical,  the  superior  directed  backwards,  the  inferior  forwards ; the  spinal 
hole  or  canal  is  small  and  oval ; the  spinous  processes  are  long,  of  a prismatic 
or  triangular  form,  bent  downwards  very  much,  or  imbricated,  and  tuber- 
cular at  their  extremities.  The  1st  has  the  body  long  transversely,  and  on 
either  side  a full  depression  above  for  the  head  of  the  1st  rib,  and  half  of  a 
similar  cavity  below  for  the  upper  part  of  the  head  of  the  second  rib;  its 
spinous  process  is  thick,  long,  and  horizontal,  and  its  articular  processes  are 
oblique  : the  10th  has  also  a full  depression  for  the  10th  rib,  the  lltli  and  12th 
in  like  manner;  these  also  want  the  articulating  depressions  on  the  trans- 
verse processes;  the  12th  also  resembles  the  lumbar,  in  the  shape  of  its  body, 
and  inferior  articular  processes. 

The  cervical  vertebrae  are  seven  in  number  and  smaller  than  the  others; 
their  body  is  long  transversely,  a little  deeper  before  than  behind  ; the  lower 
surface  is  concave  from  behind  forwards,  the  upper  is  larger  or  broader,  and 
concave  from  side  to  side ; the  structure  is  more  compact  than  in  the  dorsal 
and  lumbar;  the  laminae  are  long  and  narrow,  sharp  and  small  superiorly, 
round  and  large  interiorly,  so  as  to  overlap  those  below;  the  spinal  hole  is 
large  and  triangular;  the  notches  are  small  and  anterior  to  the  articular  pro- 
cesses ; they  are  nearly  of  equal  size  above  and  below;  the  spinous  process 
is  short,  horizontal  and  bifid  ; the  transverse  process  is  short,  bifid,  grooved 
above  for  the  nerves,  and  perforated  near  its  base  by  a round  hole  for  the 
vertebral  vessels ; it  is  on  a plane  anterior  to  the  transverse  processes  of  the 
32 


:5  0 


THE  DUELIN  DISSECTOR, 


back^or  loins,  and  appears,  on  account  of  its  foramen,  to  have  a second  or 
anterior  root  from  the  body  of  the  vertebra : the  articular  processes  are  oblique, 
the  superior  oval,  slightly  convex,  look  upwards  and  backwards;  the  inferior 
also  oval,  are  concave,  and  directed  downwards  and  forwards. 

The  1st  cervical  vertebra  or  atlas  differs  from  the  remaining,  in  having  a 
mere  bony  ring,  without  any  distinct  body  or  spinous  process,  the  anterior 
part  of  this  ring  is  tubercular  before,  but  presents  posteriorly  a smooth  and 
concave  oval  articulating  surface  which  receives  the  odontoid  process  of  the 
2d  vertebra : the  margin  of  this  ring  gives  attachment  to  ligaments ; it  is  round 
and  thick  behind,  with  a tubercle,  instead  of  spine  for  the  attachment  of  the 
recti  muscles  ; the  spinal  hole  is  very  large  and  divided  into  two  by  the  trans- 
verse ligament,  which  arises  from  two  tubercles  placed  on  the  inner  side  of 
the  superior  articulating  processes  ; the  anterior  portion,  small,  receives  the 
tooth-like  process  of  the  2d  vertebra,  the  posterior  forms  the  spinal  canal,  the 
laminae  are  thick  and  round  behind,  but,  near  the  articulating  processes,  arc 
grooved  above  for  the  vertebral  artery,  and  below  for  the  2d  spinal  nerve ; 
before  these  notches  are  the  articular  processes,  the  superior  horizontal,  con- 
cave, oval  from  before  backwards, look  upwards  and  inwards,  and  receive  the 
occipital  condyles;  the  inferior  are  nearly  flat,  circular,  and  inclined  a little 
inwards;  the  transverse  processes  are  long,  and  end  in  an  obtuse  point,  the 
anterior  root  is  slender,  the  posterior  is  long  and  large,  the  hole  between  the^e 
is  larger  than  in  the  other  vertebrae, and  is  directed  upwards  and  backwards; 
from  this  a groove  for  the  vertebral  artery  winds  backwards  round  the  supe- 
rior articular  process.  In  the  adult  the  atlas  is  very  compact ; in  the  foetus 
its  ossification  takes  place  from  five  points,  one  for  the  anterior  arch,  two  for 
the  posterior,  and  one  for  each  lateral  part. 

The  axis  or  2d  vertebra  is  remarkable  for  the  length  of  its  body,  which  has 
anteriorly  a central  ridge  between  two  depressions  for  muscles,  and  from  its 
upper  part  there  rises  bya  sort  of  a neck,  a large,  found,  dentiform  ( odontoid ) 
process,  the  fore-part  of  which  is  received  into  the  small  articulating  cavity  on 
tiie  anterior  arch  of  the  atlas,  while  posteriorly  it  presents  a small,  smooth 
convexity,  which  moves  against  the  smooth  surface  of  the  transverse  ligament 
of  the  atlas;  the  apex  is  rather  pointed,  to  it  and  to  the  sides  of  this  proce>; 
the  lateral  or  check  ligaments  are  attached  ; the  laminae  are  very  strong;  the 
superior  notches  are  behind,  the  inferior  before  the  articular  processes ; the 
spinal  hole  is  large  and  heart-shaped  ; the  spinous  process  is  forked  and  very 
strong,  its  under  surface  is  channelled  ; the  superior  oblique  processes  are 
slightly  convex,  nearly  horizontal,  and  look  a little  outwards;  the  inferior 
are  smaller,  flat,  and  look  downwards  and  forwards ; the  transverse  processes 
are  short,  arise  from  the  outside  of  the  superior  articular  processes,  are  bent 
downwards,  and  are  not  bifid;  the  hole  is  directed  obliquely  upwards  and 
outwards.  This  vertebra  in  the  foetus  has  an  additional  point  of  ossification 
in  the  odontoid  process.  It  is  articulated  directly  with  the  atlas  and  the  3d 
vertebra,  and  indirectly  with  the  occipital  bone. 

The  seventh  cervical  vertebra  is  large,  its  spine  is  very  prominent,  and  not 
bifid  ; its  transverse  process  is  seldom  perforated,  as  in  the  other  cervical 
vertebrae ; when  there  is  a foramen  in  it,  it  transmits  the  vertebral  vein  and 
not  the  artery ; in  this  vertebra  an  additional  point  of  ossification  is  found 


OR  MANUAL  OF  ANATOMY. 


251 


in  the  pedicle  which  connects  the  processes  to  the  body;  this  sometimes 
increases  beyond  the  transverse  process,  so  as  to  resemble  a supernumerary 
or  a cervical  rib. 

The  length  of  the  vertebral  column  is  generally  about  a third  of  that  of  the 
whole  body ; the  lumbar  and  cervical  regions  are  nearly  equal,  and  each  about 
half  the  length  of  the  dorsal,  the  latter  commonly  measures  12  inches,  and 
each  of  the  former  about  6.  Its  general  form  is  that  of  a pyramid,  the  base 
below ; but  when  accurately  examined  it  will  be  found  to  represent  three 
pyramids;  the  first  has  its  apex  in  the  third  cervical  vertebra,  surmounted  by 
the  axis  and  atlas,  and  its  base  is  in  the  first  dorsal,  which  is  also  the  base  of 
the  second  pyramid  whose  apex  is  in  the  fifth  dorsal,  where  also  is  the  apex 
of  the  third  pyramid,  whose  base  is  at  the  sacrum  ; the  vertebrae  diminishing 
in  size  about  the  4th  and  5th  dorsal.  The  column  is  convex  anteriorly  in  the 
neck,  concave  in  the  back,  and  convex  in  the  loins ; these  curvatures  are  caused 
by  the  different  thickness  of  the  bodies  of  the  vertebrae  before  and  behind  ; and 
of  the  intervertebral  ligaments  in  these  three  situations.  A perpendicular 
line  passed  through  the  centre  of  the  apex  and  base  of  the  column  will  be  found 
anterior  to  the  dorsal,  and  posterior  to  the  cervical  and  lumbar  vertebrae.  In 
the  dorsal  region  there  is  generally  a lateral  curvature  also,  which  is  usually 
concave  to  the  leftside;  this  direction  of  this  curve  has  been  by  some  ascribed 
to  the  pressure  of  the  aorta  on  the  left  side,  by  others,  and  with  more  proba- 
bility, to  the  effect  of  muscular  action,  for  as  the  muscles  of  the  right  arm  are 
the  most  used,  the  points  of  the  spine  to  which  these  are  attached  will  be 
drawn  towards  that  side;  in  the  several  violent  exertions  also, such  as  pulling 
forcibly,  the  body  is  usually  bent  to  the  left  side.  The  column  is  covered 
anteriorly  by  the  anterior  common  ligament,  and  in  the  neck  by  the  recti  and 
longi  muscles,  in  the  back  by  the  vena  azygos  and  aorta,  arid  in  the  loins  by 
the  crura  of  the  diaphragm,  the  aorta,  vena  cava,  and  sympathetic  nerves  ; 
posteriorly  the  column  presents  in  the  median  line,  the  spinous  processes  short, 
horizontal,  and  separate  in  the  cervical  and  lumbar,  but  close  and  bent  over 
one  another  in  the  dorsal  region  ; on  each  side  of  these  are  the  vertebral  grooves, 
which  are  wide  in  the  neck,  but  deep  and  narrow  in  the  back  and  loins  ; these 
are  filled  by  the  extensor  muscles:  the  apertures  between  the  laminae  are 
closed  by  the  yellow  ligaments,  and  covered  by  these  muscles;  outside  these 
grooves  in  the  neck  and  loins  lie  the  oblique  or  articular  processes,  but  in  the 
back  the  transverse  processes,  which  in  this  region  are  on  a plane  posterior  to 
those  in  the  neck  and  loins : the  intervertebral  or  the  holes  of  conjunction  in 
the  dorsal  and  lumbar  regions  are  before  the  transverse  processes,  but  in  the 
neck  between  them;  in  the  back  they  are  behind  the  cavities  for  the  heads  of 
the  ribs.  The  spine  supports  the  head  and  chest,  and  combines  strength  with 
lightness  and  flexibility ; it  serves  as  the  centre  of  all  themotionsof  the  trunk, 
and  transmits  the  weight  it  bears  to  the  sacrum  and  pelvis  ; it  gives  insertion 
to  numerous  muscles,  and  lodges  and  protects  the  medullaspinalis  in  the  9pinal 
canal;  this  canal  is  large  and  triangular  in  the  neck  and  loins,  round  and 
contracted  in  the  back.  The  spinal  column  is  nearly  straight  or  perpendicular 
in  the  child  ; in  the  fcetus  the  pyramidal  figure  is  reversed,  the  base  being  in 
the  cervical  and  dorsal  vertebrae,  the  apex  in  the  lumbar  and  sacral. 


252  .j 


THE  DUBLIN  DISSECTOR, 


the  thorax  or  chest. 

Is  formed  by  the  12  dorsal  vertebrae,  already  described,  by  the  sternum  and 
12  pair  of  ribs. 

The  Sternum  is  situated  at  the  forepart  of  the  chest,  in  the  median  line,  and 
in  a direction  from  above  downwards  and  forwards  ; of  a fiat  and  elongated 
form,  broad  above,  narrow  in  the  middle,  and  pointed  below  ; its  anterior 
surface  is  covered  by  the  skin  and  pectoral  aponeurosis,  is  marked  bv  four 
transverse  lines  which  indicate  its  original  division  into  five  pieces  ; the  two 
upper  lines  are  most  prominent;  the  posterior  surface  is  smooth  and  concave, 
gives  attachment  to  muscles,  and  looks  toward  the  anterior  mediastinum  ; the 
edges  are  thick,  and  present  seven  depressions  for  the  cartilages  of  the  true 
ribs  ; the  superior  of  these  is  round,  and  the  margin  of  it  is  often  continuous 
with  the  1st  costal  cartilage;  the  remaining  depressions  are  angular,  and  most 
of  them  correspond  to  the  transverse  lines  or  ridges;  hence  these  sockets  are 
more  distinct  in  the  young  than  in  the  old ; they  are  all  covered  with  cartilage 
and  separated  from  each  other  by  notches.  The  upper  or  clavicular  end  of 
the  sternum  is  broad,  thick,  and  concave  from  side  to  side,  for  the  lodgment 
of  the  interclavicular  ligament,  and  is  hollowed  out  at  each  angle  for  articula- 
tion with  the  clavicle,  into  a shallow  sigmoid  cavity  covered  with  cartilage 
and  directed  outwards  and  backwards;  this  surface  is  slightly  convex  from 
before  backwards;  the  inferior  extremity  is  long  and  thin,  and  ends  in  a car- 
tilaginous epiphysis,  the  xiphoid  or  ensiform  cartilage ; this  is  som  times  pointed , 
sometimes  bifid,  thick  or  thin,  turned  forwards  or  backwards,  and  sometimes 
perforated  by  a central  hole  ; it  remains  cartilaginous  to  a late  period  of  life  ; 
to  it  the  abdominal  muscles  and  the  costo-xiphoid  ligament  are  attached.  The 
sternum  in  the  foetus  is  separable  into  fouror  five  pieces,  in  theadultinto  two 
The  upper  piece  is  the  larger  and  thicker  of  the  two,  and  somewhat  square, 
its  edges  receive  the  cartilages  of  the  1st  rib,  and  half  of  those  of  the  second  ; 
its  lower  edge  is  nearly  straight,  and  united  to  the  2nd  piece  by  a cartilage 
which  sometimes  admits  of  slight  motion  between  the  two,  but  which  in  old 
persons  is  generally  found  ossified  : a foramen  is  sometimes  observed  in  this 
piece  of  the  sternum.  The  2nd  piece  is  longer  and  narrower  than  the  first, 
its  edges  are  marked  by  five  depressions  for  the  five  lower  true  costal  carti- 
lages, and  at  its  superior  angle  by  half  a notch,  which  joined  to  a similar 
notch  in  the  first  piece,  formed  the  cavity  for  the  2nd  cartilage;  the  five  lower 
notches  approximate,  and  the  last  is  frequently  completed  by  the  xiphoid  car- 
tilage. This  bone  consists  of  a very  spongy,  cellular,  and  vascular  tissue, 
covered  on  each  surface  by  a compact  layer. 

The  Ribs  are  twelve  on  each  side  ; they  extend  in  an  arched  manner  fmm 
t he  vertebra  towards  the  sternum,  to  which  the  seven  superior  are  attached  by 
separate  cartilages  ; these  are  the  true  or  the  sternal  ribs ; the  five  inferior  do 
not  form  complete  circles,  and  are  connected  anteriorly  to  each  other,  and  to 
the  cartilage  of  the  last  true  rib,  and  are  named  false  ; the  two  last  of  these 
are  sometimes  called  the  floating  ribs ; the  length  of  the  ribs  gradually  in- 
creases from  the  1st  to  the  8th,  and  then  diminishes  to  the  last ; the  breadth 
gradually  diminishes  from  the  1st  to  the  12th,  but  in  each  rib  it  is  greatest  near 
the  sternum;  the  1st  is  nearly  horizontal,  the  succeeding  gradually  incline 


OR  MANUAL  OF  ANATOMY. 


£53 


downwards,  so  as  to  be  lower  before  than  behind ; the  external  surface  of  each 
is  convex  and  smooth,  and  gives  attachment  to  different  muscles ; the  internal 
is  concave,  and  lined  by  the  pleura ; the  upper  border  is  round  and  smooth, 
and  gives  attachment  to  the  intercostal  muscles  ; the  inferior  is  thin,  and 
marked  with  a groove,  which  is  deep  posteriorly  for  the  intercostal  vessels  ; 
this  also  gives  attachment  to  the  intercostal  muscles.  The  posterior  end  of 
the  rib  presents  a head,  neck,  and  tuberosity ; the  head  is  round,  and  divided 
by  a ridge  into  two  articular  surfaces,  which  are  received  into  the  depressions 
in  the  dorsal  vertebras;  an  intervertebral  ligament  is  attached  to  the  middle 
ridge.  The  head  is  supported  by  the  neck,  which  is  narrow  and  round,  and 
lies  in  front  of  the  transverse  process,  to  which  it  is  connected  posteriorly  by 
the  middle  costo-transverse  ligament.  Beyond  the  neck  is  the  tubercle,  which 
looks  backwards  and  downwards,  and  is  divided  into  two  portions  : the  internal 
of  these  is  smooth  for  articulation,  with  the  transverse  process  of  the  inferior 
of  the  two  vertebrae,  to  whose  bodies  the  head  of  the  rib  is  connected ; the 
outer  portion  is  rough  for  the  insertion  of  the  external  or  posterior  costo-trans- 
verse lkrament.  External  to  the  tubercle  is  a rough  line,  which  marks  the 
turn  or  angle  of  the  rib ; this  ridge  gives  insertion  to  the  tendon  of  the  sacro- 
lumbalis  muscle;  it  descends  obliquely  forwards  ; it  is  close  to  the  tubercle 
on  the  1st,  but  the  distance  between  these  increases  in  the  succeeding  ribs  to 
the  11th  ; the  angle  is  not  distinct  on  the  12th.  The  anterior  or  sternal  end 
is  thin,  broad,  and  hollowed  into  an  oval  pit  for  the  insertion  of  the  costal 
cartilage.  The  1st  rib  is  short,  broad,  nearer  the  axis  of  the  chest  than  the 
others,  has  no  angle,  and  therefore  is  not  twisted,  but  represents  nearly  a 
horizontal  semicircle ; its  external  surface  is  directed  upwards,  and  is  marked 
by  two  grooves  for  the  subclavian  vein  and  artery,  into  the  intervening  ridge 
the  anterior  scalenus  muscle  is  inserted ; the  head  cf  this  rib  is  undivided, 
there  is  no  groove,  the  sternal  end  is  very  strong.;  the  11th  rib  has  no  groove 
or  tubercle,  its  head  is  also  undivided  ; the  12th  has  neither  angle,  tubercle, 
or  groove,  and  is  very  short.  The  ribs  are  formed  of  a cellular  structure 
covered  by  compact  and  strong  laminae,  which  often  present  a scaly  appear- 
ance ; they  are  hard  and  elastic.  In  the 'foetus  each  rib  presents  three  points 
of  ossification,  one  for  the  head,  another  for  the  tubercle,  and  the  third  for  the 
body  or  shaft. 

The  Costal  Cartilages  are  twelve  in  number ; the  1st  is  very  broad  but 
short,  the  length  increases  in  the  succeeding  to  the  seventh,  and  then  decreases 
to  the  last ; the  1st  descends  a little,  the  2d  is  nearly  horizontal,  the  succeed- 
ing ascend  more  and  more;  the  costal  end  of  each  is  convex,  and  implanted 
in  the  rib;  the  sternal  end  of  the  seven  superior  in  the  sternum,  those  of  the 
three  superior  false,  are  blended  together,  and  those  of  the  two  last  are  pointed 
and  unattached.  The  costal  cartilages  are  the  strongest  and  longest  in  the 
body;  they  are  flexible  and  elastic,  and  have  a great  tendency,  particularly 
the  four  or  five  superior,  to  ossification ; they  then  become  opaque  and  very 
compact;  in  their  natural  state  they  appear  destitute  of  vessels,  nerves,  or 
any  organic  texture,  but  are  enveloped  by  a vascular  membrane. 

The  Thorax , composed  of  the  foregoing  bones  and  cartilages,  resembles  a 
truncated  cone,  the  base  below,  the  apex  above,  flattened  before  and  behind  ; 
in  some  from  the  effect  of  dress,  it  is  of  an  ovoid  form,  being  contracted  at  the 
lower  part  and  wide  in  the  middle ; the  anterior  wall  leads  obliquely  downwards 


254 


THE  DUBLIN  DISSECTOR, 


and  forwards,  and  is  shorter  than  the  posterior,  which  is  more  vertical, 
and  rendered  very  irregular  by  the  vertebral  grooves,  and  the  angles  of  the 
ribs ; the  sides  are  convex,  particularly  behind ; the  intercostal  spaces  are 
short,  but  wide  above,  long  and  narrow  in  the  middle,  and  again  short  below; 
they  are  broader  before  than  behind.  The  apex  is  small,  transversely  oval, 
and  very  oblique  from  behind  forwards  and  downwards;  it  is  bounded  by  the 
first  ribs,  sternum  and  vertebral  column;  the  trachea,  oesophagus,  and  the 
cervical  vessels  and  nerves  pass  through  it;  the  base  is  very  large,  also  trans- 
versely oval,  and  very  oblique  from  before  backwards  and  downwards,  it  is 
bounded  by  the  xiphoid  cartilage,  the  conjoined  cartilages  of  the  false  ribs,  and 
the  vertebral  column  ; it  presents  a great  notch  anteriorly,  in  which  the  xiphoid 
cartilage  is,  and  posteriorly  a small  notch  on  each  side  for  the  vertebral  column. 
The  axis  of  the  chest  is  oblique  from  above  downwards  and  forwards,  in  con- 
sequence of  the  oblique  direction  of  the  sternum,  hence  if  a line  be  made  to 
ascend  perpendicularly  from  the  base,  it  will  pierce  the  upper  part  of  the 
sternum;  and  not  pass  through  the  apex  of  the  cavity.  The  dimensions, 
and  even  the  form  of  the  chest,  vary  in  different  individuals  and  at  different 
ages. 

THE  PELVIS. 

The  Pelvis  is  the  deep  circular  cavity  at  the  lower  end  of  the  trunk, 
b unded  by  the  sacrum,  coccyx,  and  two  ossa  innominata;  the  latter  in  the 
young  subject  can  be  separated  each  into  three,  the  ilium,  ischium,  and  pubis. 

The  Sacrum,  in  the  erect  position  of  the  body,  is  placed  at  the  upper  and 
back  part  of  the  pelvis  between  the  last  lumbar  vertebra  above,  the  coccvx 
below,  and  the  ossa  innominata  on  either  side ; of  a triangular  form,  the  base 
resembles  a vertebra,  looks  upwards  and  forwards,  is  very  broad  transversely, 
and  presents  in  the  middle  an  oval  surface  or  body  cut  oft’ obliquelv  from 
before  backwards  and  upwards,  and  covered  with  cartilage  for  articulation 
with  the  last  lumbar  vertebra,  its  anterior  edge  is  named  the  promontory  ; 
behind  this  is  the  triangular  aperture  of  the  sacral  or  spinal  canal,  and  on 
each  side  of  it  is  a smooth  convex  surface  (or  transverse  process)  directed 
forwards  and  continuous  with  the  iliac  fossae;  on  either  side  of  the  spina! 
hole  is  the  oblique  or  articular  process,  concave  and  looking  backwards  and 
inwards  to  receive  the  articular  processes  of  the  last  lumbar  vertebra;  ante- 
rior to  each  is  a groove,  which  contributes  with  the  notch  in  the  last  vertebra 
to  form  the  last  of  the  holes  of  conjunction  for  the  passage  of  the  last  of  the 
lumbar  spinal  nerves,  and  behind  the  oblique  processes  are  the  laminae,  which 
are  sharp,  and  give  attachment  to  the  last  of  the  ligamenta  flava.  The  inferior 
extremity  or  apex  is  directed  downwards,  and  presents  a small  oval  convex 
surface  to  articulate  with  the  coccyx,  on  each  side  of  which  is  a small  notch 
for  the  last  sacral  nerve ; the  anterior  surface  is  concave  from  above  down- 
wards, flat  from  side  to  side,  marked  by  four  transverve  lines,  which  indicate 
its  original  division  into  five  pieces  resembling  so  many  vertebrae  (hence 
sometimes  called  false  vertebrae ;)  the  first  of  these  grooves  is  convex,  the 
remaining  are  concave;  on  either  side  of  the  median  line  are  the  four  ante- 
rior sacral  holes,  the  two  upper  large,  the  two  lower  small ; they  are  all  round 
and  smooth,  communicate  with  the  sacral  canal,  and  transmit  the  anterior 


OR  MANUAL  OF  ANATOMY. 


255 


sacral  nerves  ; grooves  lead  outwards  from  these  holes,  along  which  the  nerves 
run ; these  are  analogous  to  the  intervertebral  holes,  and  the  intermediate 
grooved  bone  to  the  transverse  processes  in  the  vertebral  column  above ; 
external  to  these  is  a depressed  surface,  which  gives  attachment  to  the  pyri- 
form muscle.  The  posterior  or  spinal  surface  is  convex  and  very  rough, 
presenting  in  the  median  line  four  horizontal  eminences  analogous  to  the 
spinous  processes,  which  are  often  united  into  one  ridge  ; inferior  to  these  the 
sacral  canal  ends  in  a triangular  channel,  which  is  only  closed  behind  by  liga- 
ment and  bounded  on  each  side  by  two  tubercles  or  cornua,  beneath  which  is 
a notch  for  the  last  of  the  sacral  nerves  ; these  cornua  are  sometimes  joined  to 
the  base  of  the  coccyx;  at  either  side  of  the  median  spine  are  the  four  poste- 
rior holes,  smaller  and  more  irregularly  formed  than  the  anterior;  they 
transmit  the  posterior  sacral  nerves ; external  to  these  are  a range  of  tubercles 
analogous  to  the  oblique  processes ; the  sides  or  iliac  surfaces  are  uneven, 
triangular,  broad  above,  and  consisting  of  two  portions,  one  superior,  broad, 
and  irregular,  covered  with  cartilage  for  articulation  with  the  ilium  ; the  other 
inferior,  thin,  and  attached  to  the  sacro-sciatic  ligaments.  The  sacrum,  though 
very  thick,  is  yet  light  and  spongy  and  covered  by  a thin  lamina  of  compact 
substance  ; it  is  long  and  narrow  in  the  male,  broad  and  short  and  more  curved 
in  the  female ; in  the  latter  it  is  about  four  inches  and  a half  long,  its  breadth 
above  is  nearly  the  same,  but  below  only  half  an  inch ; in  the  foetus  it  is  nearly 
straight,  and  consists  of  five  pieces,  in  each  of  which  ossification  commences 
in  several  points. 

The  Coccyx,  placed  at  the  extremity  of  the  sacrum,  is  formed  of  three  or 
four  pieces,  which  in  the  old  are  united  into  one  or  two,  but  in  the  young  are 
always  distinct;  in  the  adult  it  is  triangular,  and  prolongs  the  curve  of  the 
sacrum  anteriorly,  the  base  is  above,  with  a smooth  oval  surface  adapted  to 
the  sacrum,  and  on  either  side  of  this  is  a small  horn  or  process  which  is  also 
connected  to  the  sacrum  by  bone  or  ligament ; beneath  this  is  a notch  for  the 
last  sacral  nerve;  the  apex  is  irregularly  tubercular,  and  gives  attachment  to 
the  muscles  of  the  rectum  ; the  anterior  or  pelvic  surface  is  smooth,  supports 
the  rectum,  and  is  marked  by  two  or  three  transverse  lines,  which  indicate  its 
original  division  into  distinct  pieces ; the  posterior  or  spinal  surface  is  rough 
for  the  attachment  of  muscles;  it  is  soft  and  spongy,  its  ossification  com- 
mences by  four  or  five  points,  it  becomes  united  to  the  sacrum  earlier  in  the 
male  than  in  the  female. 

OSSA  INNOMINATA. 

As  each  os  innominatum  is  divisible  in  early  life  into  three  bones,  the  ilium, 
ischium,  and  pubis,  it  will  be  found  more  convenient  to  describe  each  of  these 
separately,  in  preference  to  considering  the  os  innominatum  as  a single  bone, 
which  however  it  really  becomes  after  puberty. 

The  os  ilium  is  situated  at  the  upper  and  outer  part  of  the  pelvis,  and 
forms  that  projection  commonly  called  the  hip ; it  is  broad,  flat,  and  triangular, 
the  base  above,  and  semicircular,  the  apex  below  forming  the  upper  and  outer 
part  o!  the  acetabulum  ; it  may  be  divided  into  the  body,  alas,  and  processes. 
The  body  is  the  inferior  constricted  portion  which  presents  three  surfaces, 
one  external,  smooth  and  concave,  forms  the  upper  and  outer  side  of  the 


256 


THE  DUBLIN  DISSECTOR, 


acetabulum;  the  second  is  anterior,  small,  triangular,  and  united  to  the  pubis ; 
the  third  is  posterior  and  joined  to  the  ischium.  The  ala  is  the  broad  fan-like 
portion  which  ascends,  inclines  outwards  and  a little  forwards ; its  external 
surface  or  dorsum  is  irregularly  convex,  rough,  and  marked  by  two  curved 
lines  from  which  the  glutasus  medius  and  minimus  arise ; above  and  behind  the 
upper  line  the  bone  is  rough  for  the  origin  of  theglutseus  maximus;  the  internal 
surface  of  the  ala  is  divided  into  three  part ; one  superior  and  anterior,  is  the 
iliac  fossa,  which  gives  origin  to  the  internal  iliac  muscle  . the  second  is  poste- 
rior, rough,  and  united  to  the  sacrum,  and  the  third  is  smooth  and  small,  and  is 
the  only  portion  of  the  ilium  that  enters  into  the  side  of  the  true  pelvis,  this 
pelvic  portion  of  the  ilium  is  above  the  sciatic  notch,  and  is  separated  from 
the  fossa  by  an  obtuse  ridge  which  is  continuous  behind  with  the  promonotary 
of  the  sacrum,  and  before  with  a similar  ridge  of  the  pubis ; this  line  is  named 
ilio-pectinea,  and  into  the  iliac  portion  of  it  the  tendon  of  the  psoas  parvus 
and  the  iliac  fascia  are  inserted.  The  processes  are,  first  the  crest,  which  in 
the  young  subject  is  an  epiphysis,  it  forms  the  upper  border  of  the  ala,  it  is 
curved  inwards  before  and  outwards  behind,  ami  gives  attachment  to  the 
three  layers  of  abdominal  muscles..  Second  anterior  superior  spine,  is  that 
prominent  projection  at  the  upper  and  fore-part  of  the  crest  and  ala,  it  gives 
attachment  to  the  muscles  and  to  Poupart’s  ligament,  between  this  and  the 
next  process  is  a notch ; third,  inferior  spine  is  above  the  outer  part  of  the 
acetabulum,  it  gives  attachment  to  one  head  of  the  rectus  femoris  muscle ; 
the  notch  between  these  two  spinous  processes  is  filled  by  the  sartorius  and 
iliacus  muscles;  internal  to  the  inferior  spine  is  a superficial  groove  along 
which  the  psoas  and  iliac  muscles  pass;  this  groove  is  bounded  internally  by 
the  ileo-pectinaeal  eminence,  which  is  common  to  the  ilium  and  pubis;  fourth, 
the  posterior  superior  spine,  is  the  posterior  termination  of  the  crest,  below 
which  is  a notch  ; and  fifth,  the  posterior  inferior  spine  ; these  two  processes 
give  attachment  to  ligaments  and  muscles,  beneath  the  inferior  is  the  com- 
mencement of  the  sacro-sciatic  notch. 

The  Ischium  is  placed  at  the  lower,  outer,  and  back  part  of  the  pelvis,  and 
presents  a body  and  processes : the  body  forms  the  outer  and  back  part  of  the 
acetabulum,  more  than  two-fifths  of  which  it  forms,  and  presents  a prominent 
line  or  border;  beneath  this  is  a horizontal  groove,  which  lodges  the  tendon 
of  the  obturator  externus,  and  from  this  a rough  ridge  leads  down  to  the  tuber 
of  the  bone  and  gives  attachment  to  the  quadratus  femoris  muscle ; the  ante- 
rior part  is  thin  and  sharp,  and  bounds  the  thyroid  hole ; the  posterior  part 
joins  the  ilium,  ancf  bounds  the  sacro-sciatic  notch.  The  processes  are,  first 
the  spine , which  arises  from  its  posterior  part  just  below  the  notch  ; it  projects 
backwards  and  inwards,  gives  attachment  to  the  superior  gemellus  and  the 
lesser  sciatic  ligament,  and  bounds  the  great  sciatic  notch  interiorly;  below 
the  spinous  process,  between  it  and  the  following  is  the  smooth  pulley  round 
which  the  tendon  of  the  obturator  intemus  muscle  turns ; 2d,  the  tuberosity 
is  beneath  this  pulley  and  the  lesser  sacro-sciatic  notch,  on  this  process  the 
body  rests  in  the  sitting  posture,  it  is  broad  behind  and  covered  with  cartilage, 
it  gives  attachment  to  the  adductor  magnus  and  to  the  hamstring  muscles  : 
on  its  internal  side  is  a groove  for  the  tendon  of  the  obturator  externus ; 3d, 
the  ramus  ascends  from  the  tuber  forwards  and  inwards,  and  joins  that  of 
he  pubis ; it  is  thin  and  flat,  one  border  is  thin  and  bounds  the  thyroid  hole. 


OR  MANUAL  OF  ANATOMY. 


2 57 


the  other  is  thick  and  in  part  bounds  the  lower  aperture  of  the  pelvis,  to  it  are 
attached  the  crus  penis,  and  the  compressor  penis  muscle. 

The  Os  Pubis  is  situated  at  the  forepart  of  the  pelvis,  and  internal  part  of 
the  acetabulum ; it  may  be  divided  into  its  body  and  processes ; the  body  is 
the  most  external,  it  is  thick,  and  forms  the  internal  and  superior  part  of  the 
acetabulum,  above  which  it  joins  the  ilium  in  the  ilio-pectingsal  eminence,  and 
below  it  is  united  to  the  body  of  the  ischium  ; from  this  the  1st  process  pro- 
ceeds, the  horizontal  ramus,  forwards  and  inwards,  smooth  and  flat  supe- 
riorly, and  covered  by  the  pectinseus,  smooth  also  posteriorly  towards  the 
cavity  of  the  pelvis,  and  grooved  beneath  for  the  obturator  foramen ; a sharp 
ridge  separates  its  superior  from  its  posterior  surface ; this  ridge  is  the  ante- 
rior part  of  the  linea  ileo-pectinaea,  into  it  the  pectinaeus  muscle  and  Girnber- 
naut’s  ligament  are  inserted ; at  the  internal  extremity  of  this  ramus  and  of 
this  line  is  the  2nd  process,  the  tuberosity  or  spine ; this  is  a prominent 
tubercle  into  which  Poupart’s  ligament  is  inserted ; from  this  spine  the  3rd 
process,  the  crest,  leads  transversely  inwards;  it  is  about  an  inch  in  length; 
the  rectus  abdominis  and  pyramidalis  muscles  arise  from  it;  at  its  internal 
end  is  the  4th  process,  the  symphisis ; this  descends  nearly  vertical,  and  is 
joined  to  the  opposite  one  by  an  intervening  cartilage ; as  the  symphisis  turns 
down  from  the  transverse  crest  there  is  the  angle  of  the  pubis  ; from  the  lower 
part  of  the  symphisis  descends  the  5th  process,  the  inferior  or  descending 
ramus  in  an  oblique  direction  backwards  and  outwards,  to  meet  the  ramus  of 
the  ischium ; this,  with  the  ramus  of  the  opposite  pubis,  forms  the  arch  of  the 
pubis,  its  outer  edge  assists  in  bounding  the  thyroid  hole. 

The  Acetabulum  or  articular  cavity  for  the  head  of  the  thigh  bone  is  formed 
by  the  junction  of  the  bodies  of  these  three  bones  in  different  proportions ; 
the  ischium  constitutes  a little  more  than  two-fifths,  the  ilium  somewhat  less 
than  two-fifths,  and  the  pubis  the  remainder ; it  is  surrounded  by  a prominence 
which  is  deficient  or  notched  at  only  one  point,  this  notch  in  the  border  is 
opposite  the  thyroid  hole,  and  between  the  ischium  and  pubis,  through  it  the 
articular  vessels  pass  ; a rough  surface,  the  only  part  uncovered  by  cartilage, 
leads  from  it  to  the  centre  of  the  cavity ; to  this  the  articular  ligament  and  a 
quantity  of  adipose  membrane  are  connected;  this  cotyloid  cavity  looks  out- 
wards, downwards,  and  forwards,  the  upper  and  outer  portion,  by  which  the 
weight  is  transmitted  to  the  thigh,  is  the  deepest,  it  is  shallow  at  the  lower 
and  internal  part. 

The  Pelvis,  which  is  thus  made  up  of  the  ossa  innominata,  the  sacrum,  and 
coccyx,  may  next  be  examined  on  its  external  and  internal  surface ; anteriorly 
and  externally  it  presents  the  symphisis  and  crests  of  the  pubes;  the  ileo- 
pectinmal  eminences,  and  beneath  these  the  acetabula  and  the  thyroid  holes, 
.more  laterally  is  the  dorsum  of  the  ilium,  marked  by  its  curved  lines,  poste- 
riorly the  sacral  spines  occupy  the  median  line ; external  to  these  are  the 
sacral  foramina,  beyond  which  is  a rough  surface  for  the  attachment  of  liga- 
ments and  muscles ; and  lastly  the  great  sacro-sciatic  notch,  which  is  bounded 
by  the  sacrum,  ilium,  and  ischium.  The  superior  circumference  or  base  of 
the  pelvis,  is  inclined  upwards  and  forwards,  is  formed  on  each  side  by  the 
crest  of  the  ilium,  posteriorly  by  the  promontory  of  the  sacrum,  on  each  side 
of  which  is  a deep  notch,  which  is  filled  by  muscles,  anteriorly  by  the  iliac 


33 


25  8 


THE  DUBLIN  DISSECTOR, 


spines,  ilio-pubal  eminences,  the  intervening  grooves,  and  by  the  ossa  pubis  ; 
the  lower  or  per  inseal  circumference  or  strait  of  the  pelvis,  is  directed  down- 
wards and  backwards,  and  bounded  by  the  rami  of  the  pubes,  the  rami  and 
tubera  ischii,  and  by  the  sacrum  and  coccyx,  this  strait  presents  three  great 
notches:  1st,  the  arch  of  the  pubis,  triangular,  and  placed  beneath  the  svm- 
phisis,  the  2nd  and  3rd  are  placed  between  the  sacrum  and  os  innominatum, 
very  large  in  the  dried  bones,  but  in  the  recent  state  they  are  divided  by  the 
sciatic  ligaments,  each  into  two,  the  great  or  superior,  the  lesser  or  inferior 
sacro-sciatic  notch;  the  former  transmits  the  pyriform  muscle,  the  glutaeal, 
sciatic,  and  pudic  vessels  and  nerves,  the  latter  the  tendon  of  the  obturator 
muscle,  and  the  pudic  vessels  and  nerves.  The  internal  surface  of  the  pelvis 
is  divided  into  two  by  the  prominent  line  before  mentioned,  the  linea  ilio  pec- 
tinaea,  which  leads  from  the  spine  of  the  pubis  to  the  promontory  of  the  sacrum, 
below  this  line  is  the  true  pelvis,  above  it  is  the  false  pelvis,  which  is  rather  a 
portion  of  the  abdomen  ; this  line  is  more  distinct  posteriorly  than  anteriorly ; 
this  abdominal  or  upper  strait  of  the  pelvis  is  somewhat  elliptical,  the  greatest 
diameter  being  transverse.;  it  is  measured  by  four  lines  or  diameters  ; 1st,  the 
antero-posterior  or  sacro-pubic  is  smallest  on  account  of  the  projection  of  the 
sacrum  ; 2nd,  the  transverse  or  iliac  which  crosses  the  1st  at  right  angles  and 
is  the  greatest;  3d  and  4th,  the  oblique  which  lead  from  one  ilio  sacral  articu- 
lation to  the  opposite  ilio  pubal  eminence,  or  the  cotyloid  wall.  Above  this 
strait  the  great  or  false  pelvis  expands  and  is  deficient  in  bone  anteriorly, 
being  only  closed  by  the  abdominal  muscles,  Beneath  this  strait  is  the  true 
pelvis,  which  is  a sort  of  curved  canal  longer  than  the  false  pelvis  and  wider 
about  the  centre  than  at  either  strait,  with  smooth  walls,  concave  posteriorly 
from  above  downwards,  concave  anteriorly  in  the  transverse  direction,  and  on 
either  side  nearly  plane ; the  sacrum  and  coccyx  bound  it  posteriorly,  the 
pubes  and  thyroid  foramina  anteriorly,  and  on  either  side  a portion  of  the 
ilium  and  ischium,  the  sciatic  notches  and  ligaments.  The  pelvis  is  placed 
in  an  oblique  direction,  its  upper  orifice  looking  forwards,  so  that  if  a line  be 
passed  horizontally  from  the  upper  border  of  the  symphises  pubis  backwards, 
it  will  meet  the  middle  of  the  sacrum.  The  lower  orifice  looks  backwards 
and  downwards,  the  axis  of  the  two  orifices  therefore  is  not  the  same,  that  of 
the  superior  if  produced  would  pass  anteriorly  through  the  abdominal  mus- 
cles, between  the  pubis  and  umbilicus,  and  posteriorly  it  would,  rest  against 
the  lower  third  of  the  sacrum  ; the  axis  of  the  lower  strait  if  produced  from 
below  upwards  would  touch  the  promontory  of  the  sacrum,  these  lines  there- 
fore wifi  decussate  near  the  centre  of  the  pelvis  and  form  an  oblique  angle 
forwards.  The  axis  of  the  false  pelvis  is  nearly  vertical,  while  that  of  the 
true  cavity  is  oblique  from  above  and  from  before  downwards  and  backwards. 
The  female  pelvis  differs  from  the  male  in  several  circumstances,  it  is  wider 
and  larger,  but  not  so  deep,  the  alae  of  the  ilium  are  more  expanded,  the 
prominence  of  the  sacrum  is  less,  the  upper  strait  is  rounder  and  wider,  the 
sacrum  is  broad  and  more  concave,  the  pubic  arch  more  round  and  open,  the 
symphisis  pubis  is  not  so  deep,  the  sciatic  tuberosities  are  directed  more  out- 
wards, and  the  acetabula  are  more  distant  from  each  other ; the  male  pelvis  is 
deeper,  narrower,  and  stronger.  The  dimensions  of  the  male  and  female 
pelvis  are  given  by  Meckel  as  follows,  Tom.  ] . p.  473. 


OR  MANUAL  OF  ANATOMY. 


259 


In  the  Mnlo.  In  the  Female. 
Inches.  Lines.  Inches.  Lines. 

The  transverse  diameter  of  the  great  pelvis  between  the  anterior 

superior  spinous  processes  of  the  ilia,  - --78  8 6 

Distance  between  the  cristte  of  the  ilea,  - 8 3 9 4 

Transverse  diameter  of  the  superior  strait,  - - - 4 6 SO 

Oblique  do.  of  do.  - - - -45  4 5 

Antero  posterior  do.  of  do.  - - - -40  44 

Transverse  diameter  of  the  cavity,  - - - -40  48 

Oblique  do.  of  do.  - - - -50  54 

Antero  posterior  do.  of  do.  - - - -50  48 

Transverse  diameter  of  the  lower  strait  or  outlet,  3 0 4 5 

Antero  posterior  do,  of  do.  - - - -33  44 

The  latter  may  be  increased  to  5 inches,  from  the  mobility  of  the  coccyx 


The  ossa  innominate.  are  composed  of  two  thin  but  compact  laminae  with  an 
intervening  diploe,  the  latter  is  nearly  wanting  in  the  iliac  fossa  where  the 
bone  is  transparent,  as  well  as  in  the  cotyloid  cavity.  In  the  foetus  each  os 
innominatum  is  developed  from  three  points  of  ossification,  one  in  the  iliac 
fossa,  one  in  the  sciatic  tubercle,  and  one  near  the  spine  of  the  pubis;  these 
three  soon  unite  in  the  cotyloid  cavity.  Some  years  after  birth  the  iliac  crest 
is  developed  as  a distinct  epiphysis,  the  sciatic  tubercle  and  anterior  inferior 
spine  of  the  ilium  are  also  covered  by  distinct  plates  of  bone,  and  in  some  the 
angle  of  the  pubis;  in  some  females  also,  a plate  of  bone  or  epiphysis  consti- 
tutes the  spine  of  the  pubis  and  occasionally  grows  so  large  and  remains  so 
movable,  as  to  resemble  the  rudiments  of  a marsupial  bone.  In  the  foetus, 
the  pelvis  is  very  small  and  deep,  and  narrow  transversely;  the  true  and  false 
are  nearly  in  the  same  line,  the  acetabula  are  nearer  the  middle  line  and  look 
more  outwards,  they  are  not  beneath  the  pelvis  as  in  the  adult,  hence  the  thigh 
bones  in  the  infant  cannot  support  or  balance  the  weight  of  the  trunk. 


THE  HEAD. 

The  Head  stands  at  the  upper  extremity  of  the  vertebral  column,  is  of  a 
spheroid  figure,  compressed  on  the  sides  ; it  contains  the  brain  and  the  prin- 
cipal organs  of  sense,  and  is  divided  into  the  cranium  and  the  face.  The  cra- 
nium or  skull  is  of  an  oval  figure,  the  narrow  extremity  before ; it  contains 
the  brain,  and  is  formed  of  eight  bones,  the  frontal,  two  parietal,  two  temporal, 
the  occipital,  sphenoid  and  ethmoid;  these  bones  are  all  closely  united  by 
sutures,  in  some  of  these  are  small  bones  called  ossa  triquetra  or  Wormii ; 
the  frontal  is  considered  as  common  to  the  cranium  and  face,  but  the  tem- 
poral, ethmoid,  and  sphenoid  are  equally  entitled  to  this  distinction.  The 
anterior  region  of  the  skull  is  named  synciput  or  forehead;  the  posterior, 
occiput;  the  lateral,  the  temples ; the  upper  part  the  vertex  or  bregma;  and 
the  lower,  the  base.  The  frontal,  occipital,  ethmoid  and  sphenoid  bones 
occupy  the  median  line,  the  others  are  lateral,  and  symmetrical,  even  the 
single  bones  are  composed  of  parts  perfectly  similar  on  each  side  of  the  me- 
dian line. 

The  Frontal  Bone  at  the  upper  and  anterior  part  of  the  skull,  forms  the 
forehead,  part  of  the  temples,  of  the  orbits  and  nose  ; it  is  of  a semicircular 
form,  convex  and  smooth  anteriorly,  concave  posteriorly,  and  irregular  below, 
it  may  be  divided  into  the  superior  or  frontal  portion,  and  the  inferior  or 
orbital;  the  external  surface  of  the  frontal  part  presents  in  the  median  line, 


260 


THE  DUBLIN  DISSECTOR, 


a longitudinal  depression,  in  some  not  very  distinct,  in  others  there  is  an  ele- 
vation ; this  corresponds  to  the  line  of  union,  of  the  two  pieces  of  which  the 
bone  when  young  consisted,  it  is  parallel  to  the  longitudinal  sinus  internally, 
a suture  frequently  exists  in  it,  particularly  below;  at  the  lower  part  of  this 
line  is  the  nasal  prominence  longer  in  the  old  than  in  the  young;  the  bone 
here  is  frequently  very  porous,  it  terminates  in  a rough  edge  for  articulation 
with  the  nasal  and  superior  maxillary  bones  ; from  the  centre  of  it  projects 
the  nasal  spine  or  process , which  supports  the  nasal  bones  before,  and  the 
ethmoid  bone  behind,  on  each  side  of  this  is  a groove  which  forms  part  of  the 
superior  nasal  fossae.  On  either  side  of  the  median  line  of  the  frontal  bone 
and  proceeding  from  above  downwards  we  observe,  1st,  a smooth  surface, 
covered  by  the  occipito-frontalis  muscle;  2d,  the  frontal  eminence,  which  is 
particularly  prominent  in  the  young;  beneath  this  a slight  depression  bounded 
below  by  the  superciliary  arch  towards  the  inner  third  of  which  is  the  supra- 
orbital hole,  or  notch,  which  is  completed  into  a hole  by  a ligament,  and  which 
transmits  the  supra-orbital  nerve  and  vessels ; from  this  notch  a small  fora- 
men leads  obliquely  into  the  diploe  of  the  bone;  immediately  above  the  in- 
ternal third  of  this  arch  is  the  prominence  of  the  frontal  sinus,  and  below  it 
is  the  edge  of  the  orbit,  at  each  extremity  of  which  are  the  angular  processes  z 
the  external  is  prominent  and  joins  the  malar  bone,  the  internal  is  thin  and 
broad  and  joins  the  unguis ; above  and  outside  the  external  is  the  temporal 
ridge  or  process,  which  is  prominent  below  and  leads  upwards  and  backwards 
to  join  a similar  ridge  on  the  parietal  bone,  this  separates  the  forehead  from 
the  temple  and  gives  attachment  to  the  temporal  muscle  and  fascia.  On  the 
cerebral  or  internal  surface  of  this  portion  of  the  frontal  bone,  we  observe  in 
the  median  line  a groove  for  the  longitudinal  sinus;  interiorly  the  edges  of 
this  groove  unite  into  a ridge  to  which  the  falx  adheres,  and  which  extends 
down  to  a small  hole,  the  foramen  caecum,  which  is  between  this  bone  and  the 
ethmoid ; on  either  side  of  this  median  line  are  numerous  irregularities,  cor- 
responding to  the  convolutions  of  the  brain,  in  general,  but  not  uniformly,  for 
occasionally  a prominent  part  of  the  bone  is  opposed  to  an  eminence  of  the 
brain;  these  are  named  the  mammillary  eminences,  and  the  digital  impres- 
sions, in  some  of  the  latter  the  bone  is  often  very  thin.  The  circumference 
of  the  os  frontis  is  thick,  rough,  and  serrated  to  join  the  parietal  bones;  the 
tables  are  cut  unequally,  the  external  above,  the  internal  below,  so  that  it  rests 
on  each  parietal  above,  and  overlaps  it  below  ; below  the  temporal  process  it 
is  bevelled  off  thin  and  rough,  and  is  inserted  under  and  between  the  laminae 
of  the  ala  of  the  sphenoid  bone.  The  inferior  portion  of  the  frontal  bone 
presents  the  deep  sethmoidaj  notch  in  the  centre,  in  front  of  which  is  the  nasal 
spine  and  the  orifices  of  the  frontal  sinuses,  its  edges  are  cellular  to  unite  to 
and  communicate  with  the  ceils  of  the  ethmoid  bone ; along  its  margins  are 
two  foramina,  the  anterior  and  posterior  orbital,  they  are  common  to  this  and 
to  the  ethmoid  bone,  the  anterior  transmits  the  nasal  tw-ig  of  the  ophthalmic 
nerve  and  anterior  ethmoidal  artery,  the  posterior,  the  posterior  ethmoidal 
artery;  oil' either  side  are  the  orbital  processes  smooth,  concave,  and  trian- 
gular, the  apex  behind,  presenting  near  the  external  angular  process  a deep 
pit  for  the  lachrymal  gland,  and  near  the  internal  a slight  depression  for  the 
cartilaginous  pulley  of  the  superior  oblique  muscle  ot  the  eye,  instead  of  a 
depression  there  is  sometimes  a small  spine : the  cerebral  surface  ot  these 


OR  MANUAL  OF  ANATOMY. 


261 


processes  is  convex,  but  very  uneven,  marked  by  the  brain  and  vessels  ; their 
posterior  margins  are  thin,  and  cut  obliquely  to  support  the  lesser  wings  of 
the  sphenoid  bone.  The  processes  of  this  bone,  enumerated  by  anatomists, 
are  11,  viz.,  2 orbital,  4 angular,  2 superciliary,  2 temporal,  and  1 nasal;  the 
foramina  are  9,  viz.,  1,  the  foramen  ccecum,  2 and  3,  the  frontal  sinuses,  be- 
tween the  nasal  and  internal  angular  processes,  4 and  5,  the  supraorbital,  6 
and  7,  the  anterior,  and  8 and  9,  the  posterior  orbital  ; these  last,  as  well  as 
the  foramen  coecum,  are  often  common  to  this  and  the  ethmoid  bone.  The  os 
frontis  is  joined  to  4 bones  of  the  cranium,  viz.,  the  two  parietal,  the  sphenoid 
and  ethmoid,  and  to  8 bones  of  the  face,  viz.,  the  nasal,  superior  maxillary, 
lachrymal,  and  malar.  The  structure  is  thick  towards  the  nasal  protuberance 
and  superciliary  ridges,  but  very  thin  in  the  orbital  plates;  it  is  composed  of 
two  compact  laminae  and  an  intervening  diploe,  by  the  absorption  of  the  latter 
and  the  greater  separation  of  the  plates,  the  cavities  called  the  frontal  sinuses 
are  formed  ; these  do  not  exist  in  childhood,  and  in  the  adult  their  extent  is 
very  variable ; they  generally  extend  from  the  ethmoid  notch  upwards  and 
outwards  for  one  third  of  the  superciliary  arch,  sometimes  much  further; 
they  are  generally  separated  by  a septum ; their  use  is  not  fully  ascertained. 
This  bone  is  developed  from  two  points  of  ossification,  one  in  each  frontal 
prominence;  from  this  the  bone  extends  in  rays  which  unite  in  the  middle 
line,  but  occasionally  a suture  remains  between  them  ; this  has  been  said,  but 
without  sufficient  foundation,  to  be  more  frequent  in  women  than  in  men. 

The  Parietal  Bones  are  symmetrical,  and  form  the  upper  and  lateral  parts 
of  the  cranium ; each  is  nearly  square,  convex,  and  smooth  externally',  about 
the  centre  is  the  protuberance,  which  is  better  marked  in  children,  below  this 
is  the  curved  temporal  ridge  continuous  with  the  process  of  that  name  on  the 
os  frontis,  to  this  the  temporal  aponeurosis  adheres ; below  this  it  is  rough  for 
the  attachment  of  the  temporal  muscle ; of  the  four  edges,  the  upper  or  parietal 
is  the  longest,  it  is  serrated,  and  with  die  opposite  bone  forms  the  sagittal  su- 
ture ; the  anterior  or  frontal  edge  is  also  serrated  to  join  the  os  frontis  in  the 
coronal  suture  ; the  posterior  or  occipital  edge  is  very  irregular,  and  joins  the 
occipital  bone  in  the  lambdoid  suture;  in  this  suture  small  bones  called  ossa 
Wormii  or  triquetra  are  often  found;  the  inferior  or  temporal  edge  is  the 
shortest,  it  is  concave,  and  joins  the  temporal  bone  by  the  squamous  suture; 
of  its  four  angles  the  anterior  superior  is  nearly  right,  in  the  child  this  is 
deficient  and  the  fontanelle  exists;  the  superior  posterior  angle  is  somewhat 
rounded;  near  this  in  general  is  a foramen  which  transmits  small  vessels  from 
the  pericranium  to  the  dura  mater,  the  inferior  anterior  is  long  and  curved 
and  joins  the  sphenoid  bone,  the  inferior  posterior  is  very  irregular  and  joins 
the  mastoid  portion  of  the  temporal  bone : the  cerebral  surface  is  marked  by 
the  convolutions  of  the  brain,  and  by  the  branches  of  the  middle  artery  of  the 
dura  mater;  this  vessel  is  in  a groove,  sometimes  in  a perfect  canal  or  tube  in 
the  anterior  inferior  angle,  and  from  this  the  branches  pass  upwards  and  back- 
wards, a large  one  ascends  a little  posterior  to  the  coronal  edge;  along  the 
parietal  border  is  half  a groove,  which,  with  that  in  the  opposite  bone,  lodges 
the  longitudinal  sinus ; near  this  are  irregular  depressions  for  the  glandulse 
Pacchioni  or  the  granulations  of  the  dura  mater;  the  posterior  inferior  angle 
is  grooved  and  lodges  part  of  the  lateral  sinus:  the  structure  of  the  parietal 
bone  is  similar  to  that  of  the  frontal ; it  is  developed  from  one  point  of 


262 


THE  DUBLIN  DISSECTOR, 


ossification,  which  is  in  the  parietal  prominence;  it  is  joined  to  five  bones, 
viz.,  the  frontal,  sphenoid,  temporal,  occipital  and  to  its  fellow. 

The  Occipital  Bone  is  curved  and  of  a rhomboidal  figure  placed  at  the  pos- 
terior and  inferior  part  of  the  cranium  ; it  presents  two  surfaces,  the  external 
or  posterior,  or  basilar,  is  convex,  smooth  above,  presents  near  the  centre  the 
great  protuberance  to  which  the  cervical  ligament  is  connected  ; from  each  side 
of  this  leads  the  superior  transverse  ridge  to  which  the  occipito-frontalis,  tra- 
pezius and  complexus  muscles  are  attached  ; midway  between  this  and  the 
foramen  magnum,  is  the  inferior  transverse  ridge,  to  which  the  splenii,  recti 
majores  and  obliqui  superiores  are  attached  ; from  the  tuberosity  a spine  leads 
down  vertically  in  the  median  line  as  far  as  the  foramen  magnum  ; this  latter 
is  of  an  oval  figure,  and  transmits  the  medulla  spinalis,  the  vertebral  vessels, 
and  the  suboccipital  nerves;  it  is  larger  internally  than  externally;  in  front 
of  this  is  the  basilar  process  which  is  very  thick  and  strong,  it  passes  forwards 
and  a little  upwards  into  the  base  of  the  skull  to  join  the  sphenoid  bone;  its 
sides  are  rough  and  contiguous  to  the  petrous  bones  ; it  is  also  rough  inferior!  y 
for  the  attachment  of  muscles  and  the  mucous  membrane  of  the  pharynx ; near 
the  forepart  of  the  foramen  are  the  condyles,  smooth  and  oblong,  covered  with 
cartilage,  looking  downwards,  outwards,  and  backwards;  their  anterior  and 
inner  edges  are  the  deepest,  their  long  axis  is  from  before  backwards,  in  which 
direction,  as  also  from  side  to  side  they  are  convex,  they  are  uneven  internally 
near  their  centre,  for  the  insertion  of  the  lateral  ligaments  from  the  odontoid 
process  ; they  are  articulated  to  the  atlas  ; behind  these  is  a fossa  in  which  there 
is  generally  a small  foramen  through  which  a vein  and  small  artery  pass,  and 
before  them  is  another  fossa  in  which  there  is  always  a foramen  for  the  ninth 
pair  of  nerves;  external  to  each  condyle  is  the  jugular  eminence,  semilunar, 
bounding  posteriorly  the  foramen  lacerum,  and  giving  attachment  to  the  rectus 
lateralis  muscle.  The  upper  angle  is  acute  ; the  edges  very  irregular,  as  also 
along  the  sides,  ossa  triquetra  are  often  entangled  in  the  notches.  The  internal 
or  cerebral  surface  is  concave,  and  marked  by  two  lines  which  cross  about  the 
centre  or  opposite  the  tuberosity,  these  bound  four  fossrn,  the  two  superior 
receive  the  posterior  lobes  of  the  cerebrum,  and  are  marked  by  their  convolu- 
tions, the  inferior  are  smooth,  and  lodge  the  hemispheres  or  the  cerebellum, 
to  the  vertical  ridge  is  attached  the  falx  cerebri  above  and  falx  cerebelli  below  ; 
the  lower  extremity  of  the  latter  is  bifurcated,  the  upper  half  is  grooved  for  the 
longitudinal  sinus;  to  the  transverse  ridge  the  tentorium  is  attached,  it  isgrooved 
for  the  lateral  sinus;  the  basilar  process  is  concave  from  side  to  side,  to  support 
the  pons  Varolii  and  the  basilar  artery ; on  either  margin  of  it  is  a slight  groove 
for  the  inferior  petrosal  sinus;  on  each  side  of  the  foramen  magnum  above  the 
jugular  processes  is  a groove  for  the  lower  extremity  of  the  lateral  sinus.  This 
bone  is  joined  to  six  bones,  viz.  the  two  parietal  two  temporal,  the  sphenoid  and 
the  atlas.  Its  processes  are  six,  namely,  two  condyles,  two  jugular,  the  basilar, 
and  the  tuberosity.  Its  foramina  are  five  proper  and  two  common;  the  proper 
are,  the  magnum,  the  two  anterior  and  two  posterior  condyloid  ; the  common 
are,  the  foramina  lacera  postica  basis  cranii,  these  foramina  are  completed  by 
the  petrous  bone,  each  is  imperfectly  divided  into  two,  a small  anterior  portion 
which  transmits  the  eight  pair  of  nerves,  and  a larger  posterior  which  lodges 
the  termination  of  the  lateral  sinus  in  the  commencement  of  the  internal  jugular 
vein.  This  is  a very  hard  bone,  although  thin  throughout  except  at  the  ridges 


OR  MANUAL  OF  ANATOMY. 


265 


and  processes;  it  is  developed  from  four  points,  one  for  the  basilar  process, 
one  for  each  condyle,  and  one  for  the  upper  and  back  part. 

The  Temporal  Bones  are  situated  at  the  lateral,  middle  and  inferior  parts 
of  the  skull,  of  a very  irregular  shape,  thin  above  and  before,  and  thick  behind 
and  below  ; each  may  be  divided  into  three  portions,  the  squamous,  the  mas- 
toid, and  the  petrous.  The  pars  squamosa  is  the  superior  division,  it  is  flat, 
thin,  and  scaly,  forms  part  of  the  temporal  fossa,  is  bounded  above  by  a semi- 
circular edge,  and  below  by  the  zygomatic  process,  which  is  horizontal  and 
arises  by  two  roots,  one  anterior  covered  by  cartilage,  narrow  externally,  broad 
internally,  runs  transversely  in  front  of  the  glenoid  cavity,  the  other  passes 
horizontally  backwards,  and  bifurcates,  one  portion  turns  into  the  glenoid 
fissure,  the  other  is  gradually  lost  above  the  mastoid  process : where  these 
two  roots  of  the  zygoma  unite,  there  is  a small  tubercle  to  which  the  external 
lateral  ligament  of  the  lower  jaw  is  attached  ; the  zygoma  thence  bends  for- 
wards and  downwards,  slightly  curved,  convex  outwards,  and  ends  in  a 
serrated  edge  which  joins  the  malar  bone : between  the  root  of  this  process 
and  the  squamous  plate  there  is  a smooth  trochlea,  over  which  the  posterior 
part  of  the  temporal  muscle  moves  ; behind  the  transverse  root  of  this  pro- 
cess is  the  articular  or  glenoid  cavity,  which  is  crossed  by  the  Glasserian 
fissure  ; this  leads  inwards  and  forwards,  into  it  the  capsular  ligament  is  in- 
serted, and  near  its  centre  is  a small  hole  through  which  the  chorda  tvmpani 
nerve  and  the  laxator  tympani  muscle  pass  ; to  this  fissure  also,  the  pro- 
cessus gracilis  of  the  malleus  is  attached  ; the.  anterior  part  only  of  this  cavity 
enters  into  the  maxillary  articulation,  the  posterior  is  filled  by  the  parotid 
gland,  and  is  bounded  by  the  auditory  process  ; this  leads  inwards  and  for- 
wards behind  the  glenoid  cavity  from  the  external  auditory  hole,  which  is 
between  the  two  divisions  of  the  outer  root  of  the  zygoma;  this  process  or 
meatus  is  a twisted  plate  of  bone,  united  above  to  the  squamous  plate,  but 
presenting  below  a rugged  edge  to  which  the  cartilage  of  the  ear  is  attached  ; 
the  meatus  takes  a direction  forwards,  inwards,  and  a little  downwards,  it  is 
wider  about  the  centre  than  at  the  extremities,  it  leads  to  the  membrana  tympani. 
The  squamous  plate  internally  is  marked  by  vessels  and  by  the  convolutions 
of  the  brain  like  the  other  bones  of  the  cranium;  its  upper  edge  is  bevelled 
off  and  is  very  rough  to  overlap  the  parietal  bone.  The  mammillary  or  mas- 
toid  is  the  posterior  inferior  portion,  it  is  joined  to  the  parietal  bone  above, 
and  to  the  occipital  behind,  by  a very  deeply  serrated  edge,  inferiorly  it  is 
prolonged  into  a rough  nipple-like  process,  the  mastoid,  internal  to  which  is  a 
groove  for  the  occipital  artery,  and  another  partly  behind  it  for  the  digastric 
muscle,  above  and  behind  it  is  a hole  through  which  a vein  and  small  artery 
pass  ; this  process  is  hollowed  out  into  cells  which  communicate  with  the  tym- 
panum, it  gives  attachment  to  the  sterno-mastoid  muscle ; the  cerebral  surface 
is  deeply  grooved  for  the  lateral  sinus.  The  petrous  portion  passes  from  the 
junction  of  the  mastoid  and  squamous  forwards  and  inwards  into  the  base  of 
the  skull,  it  is  of  a triangular  form,  the  base  behind  and  very  irregular,  with 
a deep  notch  which  assists  the  occipital  bone  in  forming  the  foramen  lacerum 
posterius ; the  apex  is  anterior,  contiguous  to  the  body  of  the  sphenoid  bone, 
and  completing  with  it,  the  foramen  lacerum  anterius  which  in  the  recent 
state  is  filled  up  with  cartilage;  this  bone  is  peculiarly  hard  and  rugged  ; on 
its  inferior  surface  we  remark  in  front  of  the  foramen  lacerum  posterius  a 


264 


THE  DUBLIN  DISSECTOR, 


minute  hole  which  leads  to  the  cochlea,  and  is  named  the  aqueduct  of  the 
cochlea;  more  anteriorly  is  the  styloid  process  which  descends  obliquely  in- 
wards and  forwards,  and  gives  attachmentto  three  muscles;  it  is  surrounded 
at  its  base  or  root  by  a plate  of  bone  most  prominent  anteriorly  and  externally 
this  is  named  the  vaginal  process,  it  separates  the  glenoid  fossa  from  the  caro- 
tid foramen : behind  and  outside  the  styloid  process,  between  it  and  the  mas- 
toid, is  the  stylo-mastoid  hole  or  the  lower  end  of  the  aqueduct  of  Fallopius, 
this  transmits  the  portio  dura  or  the  facial  nerve  ; in  front  of  the  styloid 
process  is  the  carotid  hole  which  leads  into  a canal  that  winds  forwards, 
upwards,  and  inwards,  and  which  opens  within  the  cranium  above  the  fora- 
men lacerum  anterius  by  the  side  of  the  body  of  the  sphenoid  bone,  it  trans- 
mits the  carotid  artery  and  branches  of  the  sympathetic  nerve ; in  front  of 
the  carotid  hole  is  a flat  rough  surface  to  which  the  muscles  of  the  palate  are 
attached  ; the  apex  of  the  petrous  bone  is  very  irregular,  it  lies  in  the  foramen 
lacerum  anterus,  the  internal  opening  of  the  carotid  canal  is  in  it ; into  the 
angle  between  the  petrous  and  squamous  portions  the  spinous  part  of  the 
sphenoid  bone  is  wedged ; in  this  angle  there  are  two  holes  separated  by  a 
thin  lamina  of  bone,  the  upper  transmits  the  tensor  tympani  muscle,  the  lower 
is  the  extremity  of  the  bony  part  of  the  Eustachian  tube.  The  superior  or 
cerebral  surface  presents  a prismatic  form,  a sharp  angular  ridge  to  which  tire 
tentorium  cerebelli  is  attached,  separates  its  two  surfaces,  one  looks  forwards 
and  upwards,  the  other  backwards  and  inwards ; on  the  superior  we  observe 
anteriorly  a slight  depression  which  corresponds  to  the  Casserian  ganglion  of 
the  fifth  pair  of  nerves ; leading  from  this  is  a delicate  groove  which  conducts 
to  a small  opening,  the  hiatus  Fallopii,  through  which  the  superior  branch  of 
the  vidal  nerve  passes  in  order  to  enter  the  aqueduct  of  Fallopius  ; the  re- 
mainder of  this  surface  is  marked  by  the  convolutions  of  the  brain,  and  bv 
the  eminence  of  the  superior  semicircular  canal ; on  the  posterior  surface  is  the 
meatus  auditorius  internus,  through  which  pass  the  two  portions  of  the  seventh 
pair  of  nerves,  it  is  directed  forwards  and  outwards,  is  lined  by  dura  mater, 
and  is  terminated  abruptly  by  a vertical  bony  process,  beneath  which  is  a sort 
of  cribriform  plate,  through  this  the  auditory  nerve  pass,  and  above  this  the 
portio  dura  enters  the  aqueduct  of  Fallopius;  the  latter  is  a very  long  canal, 
which  leads  outwards  and  downwards  behind  the  tympanum;  the  hiatus  Fal- 
lopii and  some  canals  from  the  tympanum  open  into  it,  it  ends  in  the  stylo- 
mastoid foramen  ; behind  themeatus  is  a small  depression  lined  by  dura  mater, 
and  posterior  to  this  is  a narrow  short  slit  in  which  the  canal  of  the  vestibule 
endi>,  from  this  slit  a groove  descends  to  the  jugular  opening. 

The  petrous  bone  contains  within  it  the  complicated  apparatus  of  the  organ 
of  hearing  which  has  been  already  described.  The  temporal  bone  is  connected 
to  five  bones,  the  parietal,  malar,  sphenoid,  occipital,  and  inferior  maxillary, 
and  in  some  to  the  os  hyoides ; in  the  foetus  it  consists  of  two  portions  the 
squamous  and  petrous,  the  latter  is  large  and  well  developed,  and  the  ossicula 
auditus  which  it  contains  are  perfect,  and  nearly  as  large  as  in  the  adult,  the 
mastoid  portion  is  not  formed,  the  styloid  process  is  cartilaginous,  and  is  dis- 
tinct from  the  rest  of  the  bone,  the  external  auditory  meatus  is  wanting,  a bony 
ring  supplies  its  place  and  encircles  the  tympanum.  The  processes  enume- 
rated are  five,  viz.  the  mastoid,  auditory,  zygomatic,  styloid,  and  vaginal ; the 
holes  are  ten  proper  and  two  common  ; the  proper  are,  the  external  auditory. 


OB  MANUAL  OF  ANATOMY. 


2 65 


glenoidal,  stylo-mastoid,  mastoid,  aqueductus  cochleae,  carotid,  Eustachian, 
hiatus  Fallopii,  internal  auditory,  and  aqueductus  vestibuli ; the  common  are 
the  foramen  lacerum  anticum,  and  posticum. 

The  JEthmoid  Bone  is  situated  in  the  notch  between  the  orbital  plates  of 
the  frontal  bone,  and  forms  the  roof  of  the  nostrils ; it  is  so  named  from  its 
cribriform  or  sieve-like  appearance,  it  is  of  a cuboid  figure,  and  composed  of 
many  thin,  brittle,  semi-transparent  laminae  placed  in  every  direction  so  as 
to  form  cells,  these  enlarge  the  surface  of  the  nose  without  increasing  the  size 
or  weight,  for  this  bone  is  remarkably  light ; it  consists  of  a middle  perpen- 
dicular lamina  and  two  symmetrical  portions;  its  superior  or  cerebral  surface 
is  broad,  and  covered  by  the  dura  mater,  in  its  posterior  edge  is  a notch  which 
receives  a process  of  the  sphenoid  bone,  along  the  middle  line  is  a hard  ridge, 
which  anteriorly  rises  into  a remarkable  process,  the  crista  galli,  to  which  the 
beginning  of  the  falx  is  attached,  this  process  ends  before  in  two  short  wings 
which  join  the  os  frontis,  and  which  often  assist  in  bounding  the  foramen 
caecum ; on  either  side  of  this  process  is  a channel  deeper  before  than  behind, 
this  lodges  the  olfactory  nerves;  anterior  to  each  of  these,  and  nearer  to  the 
process,  is  a small  slit  which  transmits  the  nasal  branch  of  the  opthalmic  nerve; 
this  entire  surface  is  perforated  by  numerous  holes,  about  ten  or  twelve  of 
these  are  large  and  are  placed  over  the  lateral  parts  of  the  bone,  the  remainder 
are  very  small  and  are  on  either  side  of  the  median  line,  they  each  lead  into 
a small  vertical  canal  lined  by  dura  mater;  from  the  inferior  surface  of  this 
plate,  there  descends  the  nasal  lamella  in  the  middle  and  a large  spongy 
cellular  mass  on  either  side ; the  nasal  lamella  is  in  the  median  line.it  is 
thick  above  and  behind  where  it  joins  the  sphenoid,  thin  below  where  it  joins 
the  vomer  and  nasal  cartilage,  and  very  thick  before  where  it  unites  to  the 
nasal  process  ot'  the  os  frontis  and  to  the  nasal  bones,  its  sides  are  marked 
with  the  canals  for  the  olfactory  nerves,  short  and  oblique  before,  vertical  and 
very  long  in  the  middle  and  behind,  they  descend  for  about  half  the  depth  of 
the  plate,  and  become  converted  into  mere  grooves ; on  either  side  of  this 
septum  is  a deep  channel,  which  forms  the  roof  of  each  naris,  on  each  side  of 
this  we  observe  an  irregular  long  structure  which  consists  of  three  parts,  an 
internal  curved  lamina  (the  superior  turbinated  bone),  a middle  range  of  cells, 
and  externally  towards  the  orbit  a smooth  square  plate,  the  os  planum:  the 
turbinated  or  spongy  bone  is  a very  thin  plate  descending  at  first  vertically, 
and  then  bending  outwards,  and  rolled  upon  itself  for  nearly  half  a turn;  in 
this  is  a depression  or  sort  of  cleft,  which  is  called  the  superior  meatus  of  the 
nose,  this  channel  or  meatus  extends  along  the  posterior  half  of  the  sethmoid, 
it  is  closed  before  except  in  a small  aperture  which  leads  into  the  posterior 
sethmoid  cells  ; the  portion  of  the  turbinated  plate  which  extends  below  this 
fossa  is  named  the  middle  spongy  bone,  it  is  larger  than  the  upper  portion, 
more  curved  and  very  concave  outwardly,  beneath  this  is  a deep  fossa  named 
the  middle  meatus  of  the  nose;  the  sethmoid  cells  are  external  to  the  turbinated 
plates,  bounded  above  by  the  cribriform  plate,  and  externally  by  the  os  planum, 
the  cells  are  about  twelve  or  fourteen  in  number,  and  are  divided  by  a bony 
septum  into  an  anterior  and  posterior  set,  the  posterior  are  small,  and  open 
into  the  middle  meatus,  and  sometimes  one  of  the  uppermost  communicate 
with  the  sphenoid  sinus  or  open  into  the  fossa  of  its  turbinated  plate;  the  an- 
terior cells  are  larger  and  more  numerous,  they  open  into  the  middle  meatus, 
34 


266 


THE  DUBLIN  DISSECTOR, 


one  of  the  most  anterior  is  curved  into  a sort  of  tube,  the  infundibulum , into 
this  the  frontal  sinus  opens  above,  and  it  terminates  before  the  orifice  of  the 
great  maxillary  sinus  or  antrum;  all  these  cells  are  lined  by  the  pituitary 
membrane,  which,  however,  is  less  vascular  and  thick  than  that  on  the  nasal 
lamella  or  turbinated  bones  ; on  this  membrane,  particularly  that  covering  the 
superior  spongy  bone,  and  the  square  surface  before  it,  the  external  olfactory 
canals  chiefly  end  ; from  the  lower  surface  of  the  aethmoidal  cells  thin  plates 
of  bone  often  descend  very  irregularly  to  join  the  superior  maxillary ; external 
to  the  cells  on  each  side  is  the  os  planum  or  orbital  plate,  very  smooth  and 
polished,  articulated  above  to  the  frontal,  before  to  the  lachrymal,  behind  to 
the  sphenoid,  and  below  to  the  maxillary  and  palafe  bones,  the  upper  border 
has  often  a notch  or  two  which  assist  in  forming  the  internal  orbital  holes. 
The  sethmoid  bone  contributes  to  form  the  base  of  the  cranium,  the  nose,  and 
the  orbits;  it  has  little  or  no  cellular  tissue  in  its  composition  except  in  the 
turbinated  plates  and  the  crista  galli ; it  is  developed  by  three  points  of  ossi- 
fication, one  for  the  central  lamella  and  one  for  each  side,  the  latter  appear 
first,  the  turbinated  plates  are  not  distinct  until  five  years  of  age  : it  is  joined 
to  two  bones  of  the  cranium,  the  frontal  and  sphenoid,  and  to  eleven  of  the  face, 
the  nasal,  superior  maxillary,  lachrymal,  palate,  inferior  spongy,  and  the 
vomer. 

The  Sphenoid  Bone  is  so  named  from  the  manner  in  which  it  is  wedged  into 
the  base  of  the  skull,  in  the  middle  of  which  it  is  placed,  it  is  articulated  to 
all  the  bones  of  the  cranium,  and  to  many  of  those  of  the  face,  it  is  of  a very 
irregular  form,  and  has  been  compared  to  a bat,  to  which  it  bears  some  resem- 
blance, particularly  if  the  aethmoid  remain  attached  ; it  may  be  divided  into 
a body  and  processes,  the  body  is  in  the  centre,  and  resembles  a square  box ; 
from  its  median  line  interiorly  proceeds  the  azygos  process,  or  the  rostrum, 
which  is  received  between  the  layers  of  the  vomer,  on  each  side  of  this  is  a 
small  groove  for  vessels  ; the  body  is  flat  and  rough  posteriori}'  for  attachment 
to  the  basilar  process,  anteriorly  it  presents  the  two  small  round  openings  of 
the  sphenoid  sinus,  beneath  which  are  often  found  two  small  triangular  bones, 
the  spongy  or  turbinated  bones  of  the  sphenoid,  or  of  Bertin  ; the  superior  or 
cerebral  surface  of  the  body  presents  several  remarkable  appearances,  it  is 
hollowed  from  before  backwards  into  the  deep  depression  called  sella  turcica, 
this  lodges  the  pituitary  gland,  and  is  perforated  bv  several  holes  through 
which  small  vessels  pass  to  the  nose,  posteriorly  it  is  bounded  by  a thin  plate 
which  rises  perpendicularly,  and  has  a slight  knob  at  each  angle  named  the 
posterior  clinoid  processes,  to  each  of  these  the  extremity  of  the  convex  edge 
of  the  falx  is  attached,  anterior  to  the  sella  is  an  eminence  named  the  olivary 
process,  on  it  is  a transverse  depression  for  the  optic  commissure,  on  each  side 
of  which  are  the  anterior  clinoid  processes,  two  thick  tubercles  to  which  the 
extremity  of  the  concave  edge  of  the  tentorium  is  attached,  each  of  these  is 
perforated  by  the  optic  foramen,  which  is  transversely  oval  and  transmits  the 
opthalmic  artery  and  the  optic  nerve  ; sometimes  the  anterior  is  united  to  the 
posterior  clinoid  process  by  bone,  and  sometimes  to  the  olivary  process,  from 
each  there  extends  forwards  and  outwards  a thin  plate  of  bone,  the  transverse 
spine  or  lesser  wing,  or  wing  of  Ingrassius,  this  is  united  anteriorly  to  the 
frontal  bone,  and  forms  part  of  the  orbit,  it  ends  in  a point,  its  posterior  edge 
is  thick  and  rounded,  the  sphenoidal  fold  of  the  dura  mater  is  attached  to  it, 


OR  MANUAL  OF  ANATOMY. 


267 


and  both  occupy  the  fissure  of  Sylvius  on  the  base  of  the  cerebrum  between  its 
anterior  and  middle  lobes ; each  side  of  the  sella  turcica  is  grooved  by  the 
carotid  artery;  from  its  fore-part  extends  a small  plate  to  join  the  asthmoid 
bone  [(etknioiclal  process);  from  each  side  of  the  body  the  ala  is  continued 
outwards,  forwards,  and  upwards;  it  presents  three  surfaces,  one  anterior 
smooth  and  square  forms  part  of  the  outer  wall  of  the  orbit,  and  is  named 
orbital  process,  another  is  elongated  and  concave,  and  together  with  the  tem- 
poral bone  supports  the  middle  lobe  of  the  cerebrum ; the  third  or  external 
surface  is  named  the  temporal  process,  this  is  divided  into  two  by  a crest;  the 
upper  part  forms  a portion  of  the  temporal  fossa,  and  the  lower  of  the  zygo- 
matic fossa,  some  fibres  of  the  temporal  and  external  pterygoid  muscles  are 
attached  to  the  crest  itself;  from  the  posterior  part  of  each  wing  the  spinous 
process  extends  backwards,  and  curves  a little  downwards  and  outwards,  and 
occupies  the  angle  between  the  squamous  and  petrous  portions  of  the  temporal 
bone,  it  terminates  in  a spine,  the  styloid  process,  on.  the  inner  side  of  the 
articulation  of  the  lower  jaw,  near  this  process  is  a small  foramen  ( spinosum ) 
which  transmits  the  middle  or  spinous  artery  of  the  dura  mater,  anterior  to 
this  is  the  foramen  ovale  opening  directly  downwards  for  the  passage  of  the 
inferior  maxillary  nerve;  still  more  anterior  is  the  foramen  rotundum,  which 
leads  forwards  and  transmits  the  superior  maxillary  nerve;  between  the 
lesser  and  great  wing  is  a long  slit,  the  foramen  lacerum  orbitale,  wide  inter- 
nally, narrow  externally  where  the  frontal  bone  sometimes  assists  inclosing 
it,  it  transmits  the  3d,  4th,  first  branch  of  the  5th  and  the  6th  pair  of  nerves 
from  the  cranium  to  the  orbit;  from  the  angle  between  the  body  and  ala,  the 
pterygoid  plate  descends  perpendicularly,  internally  it  bounds  the  posterior 
naris,  externally  the  external  pterygoid  muscle  is  attached  to  it,  anteriorly  the 
palate  bone  is  connected  to  it,  posteriorly  it  is  hollowed  into  the  pterygoid 
fossa,  which  lodges  the  internal  pterygoid  muscle,  and  in  a small  depression 
internal  to  this  the  tensor  palati  muscle;  this  fossa  thus  divides  this  process 
into  two  plates,  the  external  is  broad  and  rough,  the  internal  is  longer  and 
narrower,  and  ends  in  the  hamular  process,  a small  delicate  hook,  convex 
inwards,  concave  outwards,  and  covered  by  a bursa,  round  this  the  tendon  of 
the  tensor  palati  muscle  turns  ; in  the  inferior  notch  between  these  plates  the 
palate  bone  is  received ; above  the  internal  pterygoid  plate  is  the  vidian  hole 
or  canal,  this  opens  anteriorly  on  the  inner  side  of  the  foramen  rotundum,  into 
the  spheno-maxillary  fossa,  and  posteriorly  into  the  foramen  lacerum  anterius, 
it  transmits  the  vidian  nerve  and  vessels.  The  structure  of  the  sphenoid  bone 
is  very  compact,  except  the  body  which  is  cellular;  the  latter  about  ten  years 
of  age  undergoes  the  process  of  absorption,  whereby  the  cavities  called  the 
sphenoid  sinuses  are  formed  ; these  open  into  the  upper  and  back  part  of  the 
nose ; in  front  of  them  in  the  adult  is  a small  curved  plate  of  bone,  the  sphenoidal 
turbinated  bone,  it  is  of  a pyramidal  form,  the  base  anteriorly  connected  to 
the  posterior  asthmoid  cells,  the  apex  posteriorly,  and  joined  to  the  fore-part 
of  the  sinus,  it  lies  above  the  spheno -palatine  foramen,  a hole  which  is  below 
the  body  of  the  sphenoid,  and  between  the  orbital  processes  of  the  palate  bone  ; 
this  hole  leads  from  the  nose  to  the  spheno-maxillary  space ; these  superior 
spongy  bones  are  wanting  in  the  child  and  sometimes  in  the  adult.  The  sphe- 
noid is  articulated  to  the  7 bones  of  the  cranium  and  to  5 of  the  face,  viz.,  the 
two  malar,  two  palate,  and  the  vomer,  and  in  some  cases  to  the  superior 


263 


THE  DUBLIN  DISSECTOR, 


maxillary  by  the  pterygoid  plates,  the  palate  bones  however  in  general  inter- 
vene; the  processes  enumerated  are  27,  viz.,  5 clinoid,  1 aethmoidal,  2 lesser 
wings,  1 vomer,  2 spongy  or  triangular,  2 great  wings,  2 temporal,  2 orbital, 
2 spinous,  2 styloid,  4 pterygoid,  and  2 hamular:  the  foramina  are  14  proper 
and  8 common;  the  proper  are,  2 optic,  2 lacerated  orbital,  2 round,  2 oval, 
2 spinal,  2 vidian  and  the  2 sinuses;  the  common  are,  2 foramina  lacera  antica 
basis  cranii,  2 spheno-maxillary  fissures,  one  in  each  orbit  bounded  bv  the 
orbital  plates  of  the  sphenoid,  malar,  maxillary  and  palate  bones,  2 spheno- 
palatine, and  2 posterior  palatine  canals  between  the  pterygoid  processes  and 
the  superior  maxillary  tuberosities. 

The  bones  of  the  cranium  are  connected  to  each  other  by  suture,  that  is,  the 
edge  of  each  is  serrated  or  cut  into  irregular  teeth  like  processes,  these  indi- 
gitate  or  lock  into  each  other,  so  as  to  unite  the  two  edges  in  a very  strong  and  mo- 
tionless manner,  the  indentations  are  irregular  and  oblique  in  verv  thick  bones, 
but  where  the  edges  are  thin,  the  suture  is  more  straight  and  regular,  they  are 
more  distinct  in  the  young  than  in  the  old,  and  on  the  outer  than  the  inner  sur- 
face of  the  cranium ; there  are  seven  sutures  noticed  by  most  anatomists, 
some  however  unnecessarily  enumerate  a greater  number,  the  sphenoidal,  seth- 
moidal,  coronal,  sagittal,  lambdoid  and  two  squamous.  The  sphenoidal  suture 
is  very  extensive,  it  follows  the  irregular  edge  of  the  sphenoid  bone,  and 
connects  it  to  the  occipital,  the  temporal,  inferior  angle  of  the  parietal,  the 
frontal,  and  the  asthmoid.  The  sethmoidal  suture  in  like  manner  encircles 
the  aethmoid  bone  and  connects  it  to  the  frontal.  The  frontal  or  coronal  su- 
ture proceeds  from  the  upper  extremity  of  the  sphenoidal  about  an  inch  behind 
the  external  angle  of  the  os  frontis,  ascends  vertically  inclining  a little  back- 
wards, and  then  decends  to  the  same  point  on  the  opposite  side,  it  connects  the 
frontal  and  parietal  bones  in  the  manner  before  explained.  The  sagital  suture 
leads  from  the  superior  angle  of  the  occipital  bone  directly  forwards  between 
the  two  parietal  to  the  centre  of  the  coronal  suture,  and  is  sometimes  continued 
along  the  median  line  of  the  frontal  bone  down  to  the  nose.  The  lambdoid 
suture  extends  on  either  side  from  the  posterior  extremity  of  the  sagittal  suture, 
downwards  and  forwards  to  the  mastoid  process  of  the  temporal  bone  ; a su- 
ture named  the  additamentum  of  the  lambdoid  continues  down  between  this 
process  and  the  occipital  bone  as  far  as  the  foramen  lacerum  posterius ; the 
lambdoid  suture  is  very  rough  and  frequently  containsossa  triquetra  of  very  irre- 
gular size,  it  connects  the  occipital  and  the  two  parietal  bones ; the  additamen- 
tum is  very  little  serrated,  but  presents  uneven  thick  edges,  it  connects  the 
occipital  to  the  mastoid  portion  of  the  temporal  bone,  the  mastoid  hole  is  fre- 
quently in  it,  it  nearly  corresponds  to  the  lateral  sinus.  The  squamous  suture 
on  each  side  is  continued  from  the  extremity  of  the  sphenoidal  in  an  arched 
direction  upwards  and  backwards,  as  far  as  the  inferior  angle  of  the  parietal, 
it  is  then  continued  under  the  name  of  additamentum  of  the  squamous  suture 
directly  backwards  for  about  an  inch;  the  structure  of  the  squamous  differs 
from  that  of  the  other  sutures,  the  bones  are  not  serrated  but  thin  and  scaly, 
and  over  lap  each  other,  it  unites  the  temporal  to  the  parietal ; the  additamen- 
tum is  serated  and  connects  the  inferior  angle  of  the  parietal  to  the  upper  part 
of  the  mastoid  portion  of  the  temporal  bone,  it  corresponds  to  the  course  of  the 
lateral  sinus  internally ; a small  os  triquetrum  is  sometimes  found  at  the 
anterior  part  of  this  suture,  and  seldom  in  any  other  situation. 


OR  MANUAL  OF  ANATOMY,' 


269 


OF  THE  SKULL  IN  GENERAL. 

The  outer  surface  of  the  skull  presents  4 regions,  the  superior  is  smooth 
and  even,  has  no  remarkable  appearance  deserving  more  particular  attention; 
the  lateral  regions  are  each  divided  into  two,  anterior  or  temporal,  and  the 
posterior  or  mastoid ; the  inferior  region  extends  from  the  nasal  notch  to  the 
occipital  protuberance,  and  is  bounded  laterally  by  the  zygomatic  arches,  and 
by  a ridge  which  is  continued  from  these  processes  round  the  skull  with  but 
little  interruption  ; this  region  may  be  divided  into  three  portions,  anterior, 
middle,  and  posterior  ; the  anterior  extends  from  the  superciliary  ridges  of 
the  os  frontis  to  the  roots  of  the  pterygoid  processes  of  the  os  sphenoid es ; it 
presents  the  nasal  spine  and  process  of  the  os  frontis,  the  sethmoid  bone,  the 
orbital  plates  of  the  os  frontis,  bounded  by  its  angular  processes  before,  and 
by  the  orbitar  plates  of  the  sphenoid  behind  ; in  this  division  are  the  supra- 
orbital, the  anterior  and  posterior  orbital  holes,  the  openings  of  the  frontal  and 
sethmoid  cells,  the  optic  and  lacerated  holes  of  the  orbits,  the  vidian  canals 
and  the  formina  rotunda.  The  middle  division  extends  from  the  roots  of  the 
pterygoid  to  the  styloid  processes  of  the  temporal  bones,  it  presents  the  azy- 
gos process,  the  basilar  process  of  the  os  occipitus,  the  anterior  points  of  the 
petrous  portions  of  the  temporal  bones  ; the  spinous  processes  of  Ihe  sphenoid, 
and  the  glenoid  cavities  of  the  temporal  bones.  The  holes  in  this  division  are 
the  oval,  spinous,  carotid,  external,  auditory,  glenoidal,  and  the  Eustachian 
tubes.  The  posterior  division  extends  from  the  styloid  processes  of  the  tem- 
poral to  the  tuberosity  of  the  occipital  bone  ; it  presents  the  foramen  magnum, 
the  two  condyles  the  jugular  ridge,  the  styloid  processes  of  the  temporal  bones, 
surrounded  by  their  vaginal  processes,  the  mamillary  processes,  the  digastric 
pits  the  inferior  and  superior  transverse  arches,  the  spine,  protuberance  and 
pits  of  the  occipital  bone  ; the  foramina  in  this  division  are  the  stylo-mastoid, 
mastoid,  magnum,  lascera  postica,  anterior  and  posterior  condyloid. 

The  skull  is  divided  internally  into  the  arch  or  vault  and  the  base  •,  on  the 
vault  is  to  be  observed  the  sulcus  for  the  longitudinal  sinues,  the  frontal  crest, 
the  grooves  for  the  middle  arteries  of  the  dura  mater,  the  depressions  for  the 
convolutions  of  the  brain,  and  for  the  granulations  or  glandulae  pacchionse  ; the 
base  of  the  skull  is  very  uneven,  and  presents  three  portions  on  different  planes, 
the  anterior  or  frontal,  the  middle  or  spheno-temporal,  and  the  posterior  or 
occipital ; the  1st  is  formed  of  the  orbital  plates  of  the  frontal  bone,  the  cribri- 
form plate  of  the  ethmoid,  and  the  lesser  wings  of  the  sphenoid  ; the  foramina 
in  this  division  are  the  csecum,  olfactory,  and  optic.  The  2nd  division  is 
bounded  before  by  the  transverse  spinous  processes  of  the  sphenoid,  on  the 
sides  by  the  squamous  portions  of  the  temporal,  and  behind  by  the  superior 
angles  of  the  petrous  portions  of  the  same  bone,  and  by  the  posterior  clinoid 
processes  of  the  sphenoid ; in  the  middle  is  the  sella  turcica,  on  each  side  of 
which,  but  below  it,  is  a groove  for  the  carotid  artery,  and  for  the  cavernous 
sinus,  and  below  this  is  a shallow  groove  for  the  superior  maxillary  nerve ; 
further  out  on  each  side,  are  the  cavities  to  lodge  the  middle  lobes  of  the  brain 
and  on  the  anterior  surface  of  the  petrous  bones  are  seen  the  juttings  of  the 
vertical  semi-circular  canals.  The  foramina  in  this  division  are,  the  foramina 
lacera  orbitaria,  superiora,  rotunda,  ovalia,  carotica,  spinosa,  lacera  basis  cranii 


270 


THE  DUBLIN  DISSECTOR, 


anteriora,  and  innominata  or  hiatus  Faliopii.  The  3rd  or  occipital  portion  is 
bounded  before  by  the  basilar  process,  and  by  the  posterior  surface  of  the 
petrous  bones,  and  behind  by  the  occipital,  it  presents  the  basilar  process,  the 
foramen  magnum,  the  perpendicular  ridge  of  the  occipital  crossed  bv  the 
transverse,  by  which  this  bone  is  divided  into  four  fossae,  the  superior  angles 
of  the  petrous  bones  having  a shallow  groove  for  the  superior  petrosal  sinuses, 
the  transverse  occipital  ridge,  with  a deep  one  for  the  lateral  sinuses,  which  last 
are  continued  over  the  inferior  angles  of  the  parietal  bones,  and  thence  descend 
inwards  along  the  mastoid  portions  of  the  temporal  bone,  and  then  again 
groove  the  occipital  bone,  and  pass  forwards  on  it  to  the  posterior  foramina 
lacera;  the  perpendicular  ridge  is  grooved  above  for  the  longitudinal  sinus, 
which  terminates  sometimes  in  the  left,  and  at  other  times  in  the  right  lateral 
sinus  ; the  same  ridge  below  the  tentorium  gives  attachment  to  the  falx  minor, 
and  is  slightly  grooved  for  the  occipital  sinuses.  The  foramina  in  this 
division  are  the  foramina  auditiva,  aqueductus  vestibulorum,  foramina  lacera 
postica,  foramen  magum,  foramina  condyloidea  antica  and  postica. 

THE  BONES  OF  THE  FACE. 

These  consist  of  six  pair  and  two  single  bones  ; the  six  pair  are  the  malar, 
superior  maxillary,  lachrymal,  nasal,  palatine,  and  inferior  spongy ; the  two 
single  bones  are  the  vomer  and  the  inferior  maxillary. 

The  malar  or  cheek  hone  is  placed  at  the  outer,  and  under  part  of  the 
orbit,  and  forms  the  prominence  of  the  cheek ; it  is  of  an  irregular  square 
form,  convex  externally,  and  covered  by  the  skin  and  orbicularis  palpebrarum ; 
it  presents  one  or  two  small  holes  for  vessels  and  nerves;  its  upper  and  outer 
edge  is  named  external  orbitar process,  and  joins  the  frontal  bone;  its  inner 
end  is  cut  oft'  obliquely  and  serrated,  is  attached  to  and  overlaps  the  maxil- 
lary bone,  this  is  the  maxillary  process  ; the  upper  edge  is  round,  smooth,  and 
concave,  forms  part  of  the  base  of  the  orbit  and  ends  internally  in  a long 
angle,  named  the  internal  orbital  process  ; the  lower  is  thick  and  uneven,  and 
gives  attachment  to  the  masseter  muscle,  it  ends  posteriorly  in  the  zygomatic 
process,  which  passes  backwards,  and  terminates  in  a serrated  edge  which 
supports  the  zygomatic  process  of  the  temporal  bone;  behind  this  the  malar 
bone  is  smooth,  and  forms  part  of  the  temporal  fossa;  from  the  posterior  sur- 
face a thin  plate  extends  into  the  orbit,  and  is  named  the  internal  orbited 
process  ; the  posterior  edge  of  this  is  notched  to  close  the  spheno  maxillary 
fissure  anteriorly.  The  malar  bone  is  thick,  strong,  and  cellular  ; it  is  well 
developed  in  the  foetus.  It  is  joined  to  four  bones,  the  frontal,  sphenoid, 
temporal,  and  superior  maxillary  ; the  processes  are  five,  the  superior,  inferior, 
and  internal  orbital,  the  malar,  and  zygomatic  ; the  foramina  are  two  or  three 
proper  and  one  common. 

The  superior  maxillary  bone  is  of  a very  irregular  figure  and  attached  to 
all  the  bones  of  the  face ; it  forms  part  of  the  front  of  the  face,  a portion  of  the 
orbit,  nose  and  palate  ; it  may  be  divided  into  the  body  and  processes.  The 
body  is  concave  anteriorly,  to  form  the  infra-orbital  or  canine  fossa,  in  the 
upper  part  of  which  is  the  infra-orbital  hole  ; it  is  bounded  externally  and 
above  by  a rough  serrated  surface,  the  malar  process,  which  is  smooth  and 
hollowed  out  behind  for  the  temporal  muscle  ; springing  from  the  inner  and 


OR  MANUAL  OF  ANATOMY. 


271 


upper  part  of  the  body,  is  the  nasal  process  of  a pyramidal  form,  perforated 
by  one  or  two  small  holes  for  vessels,  serrated  above  to  join  the  os  frontis, 
prominent  below,  slightly  grooved  anteriorly  to  receive  the  nasal  bone  and 
the  alar  cartilage,  and  deeply  grooved  behind  to  form  part  of  the  lachrymal 
fossa  and  duct;  its  internal  surface  forms  part  of  the  nasal  fossa,  and  is  con- 
nected to  the  ethmoid  bone  above,  below  this  is  a channel  that  leads  to  the 
middle  meatus,  and  inferior  to  this  is  a crest  for  the  spongy  bone ; between 
the  nasal  and  malar  processes  is  the  orbital  plate,  of  a triangular  form,  the 
base  joined  to  the  ethmoid,  lachrymal  and  palate  bones ; this  process  looks 
downwards  and  forwards ; its  outer  and  posterior  edge  bounds  the  spheno- 
maxillary fissure;  the  infra-orbital  canal,  which  runs  along  it  in  a direction 
forwards  and  inwards,  lodges  the  vessels  and  nerves  of  that  name;  this  canal 
divides  anteriorly  into  two,  the  smaller  is  the  anterior  dental,  which  descends 
in  the  anterior  wall  of  the  antrum,  where  it  terminates  by  communicating 
with  the  anterior  alveoli,  the  other  or  the  proper  infra-orbital  canal  is  wider, 
and  ends  in  the  infra-orbital  hole ; the  edge  of  the  bone  above  this  hole  is 
round  to  form  part  of  the  contour  of  the  orbit,  behind  which  the  inferior 
oblique  muscle  of  the  eye  arises;  behind  and  below  this  plate  is  the  tuber- 
osity, this  is  more  prominent  in  the  young,  as  it  contains  the  last  molar  tooth, 
after  the  protrusion  of  which  it  diminishes,  near  this  are  three  or  four  small 
holes,  the  posterior  dental  canals  which  lead  to  the  posterior  alveoli ; be- 
neath the  orbital  plate,  the  body  of  the  bone  is  excavated  into  a large  cavity, 
the  antrum  highmorianum,  of  a somewhat  triangular  figure,  the  base  towards 
the  nose,  the  apex  towards  the  malar  process  ; this  is  the  largest  sinus  con- 
nected with  the  nose,  it  is  sometimes  divided  by  septa  as  well  as  by  the  ante- 
rior dental  canal  into  two  or  more  cells  ; the  infra-orbital  canal  runs  along  its 
roof,  through  the  floor,  one  or  two  of  the  molar  alveoli  project  and  sometimes 
open,  the  canine  fossa  is  in  front  of  it,  and  the  tuber  bounds  it  behind,  this 
cavity  is  lined  by  the  membrane  of  the  nose  ; in  the  skeleton  the  opening  in 
its  base  is  very  large  and  irregular,  but  in  the  natural  state  it  is  contracted 
by  the  ethmoid  bone  above,  by  the  palate  bone  behind,  and  by  the  inferior 
spongy  bone  below,  also  by  the  lining  membrane  of  the  nose  ; it  opens  by  one 
or  two  small  oblique  openings  into  the  middle  meatus  of  the  nose,  anterior  to 
which  is  the  infundibulum,  a deep  groove  leading  downwards,  backwards, 
and  inwards,  from  the  frontal  sinus  and  the  anterior  sethmoid  cells,  and  open- 
ing into  the  middle  meatus;  the  body  of  this  bone  is  bounded  below  by  a 
strong  horizontal  plate  the  palatine  process,  doe.  upper  surface  of  which  is 
smooth  and  concave,  and  forms  the  floor  of  the  nose,  the  lower  is  rough,  and 
forms  the  roof  of  the  mouth;  it  is  thick  before,  thin  and  serrated  behind  to 
join  the  palate  bone,  internally  it  is  thick  and  rough,  and  joins  the  opposite 
bone,  by  a suture,  in  the  anterior  part  of  which  is  the  anterior  palatine  canal, 
which  opens  interiorly  on  the  palate  by  the  foramen  incisivum,  and  superiorly 
by  two  distinct  holes,  one  in  each  nostril ; this  internal  edge  is  raised  so  as  to 
form  the  nasal  spine  or  crest  to  receive  the  vomer,  anteriorly  this  projects  so 
as  to  form  the  anterior  nasal  spine,  to  which  the  cartilaginous  septum  of  the 
nose  is  attached  ; between  this  and  the  nasal  process  the  bone  is  very  concave 
and  forms  the  anterior  opening  of  the  nares.  The  palate  plate  is  bounded 
anteriorly  and  externally  by  the  curved  alveolar  edge  or  process  ; this  is  very 
thick  particularly  behind,  and  is  divided  into  several,  generally  eight  conical 


272 


THE  DUBLIN  DISSECTOR, 


cavities  for  the  teeth ; the  partitions  between  these  are  formed  of  dense  cellular 
texture  which  is  less  compact  posteriorly.  The  superior  maxillary  bone 
is  connected  to  two  bones  of  the  cranium,  the  frontal  and  aethmoid,  and  to 
seven  bones  of  the  face,  the  nasal,  lachrymal,  malar,  palate,  inferior,  spongv, 
vomer,  and  to  its  fellow  of  the  opposite  side,  also  to  the  teeth : it  is  sometimes 
connected  to  the  pterygoid  processes  of  the  sphenoid.  The  processes  are 
eight,  the  nasal,  orbital,  malar,  tuberosity,  alveolar  palatine,  nasal  crest,  and 
nasal  spine  ; the  foramina  are  three  proper  and  four  common  ; the  proper  are 
the  infra-orbital  the  foramen  antri,  and  foramen  incisivum ; the  common  are 
the  spheno-maxillary  fissure,  the  posterior  palatine  hole  or  canal,  the  anterior 
nares,  and  the  nasal  or  lachrymal  duct ; this  bone  is  well  developed  in  the  foetus 
with  the  exception  of  the  alveoli  and  sinus,  which  do  not  appear  for  a few  years. 

The  ■palate  bone  is  situated  at  the  outer  and  back  part  of  the  nose, 
between  the  pterygoid  processes  and  the  superior  maxillary  bone,  it  is  of  a very 
irregular  figure  and  maybe  divided  into  four  parts;  1st,  the  horizontal  or 
palate  plate,  2nd,  the  nasal  or  perpendicular  plate,  at  the  lower  and  outer 
angle  of  which  is  3rd,  the  pterygoid  process ; and  4th,  at  the  upper  extremity 
of  the  nasal  is  the  orbital  portion  ; the  palate  process  or  plate  is  nearly  square, 
fiat,  and  rough  below,  smooth  above,  and  concave  from  side  to  side  to  form 
part  of  the  floor  of  the  nose,  posteriorly  it  has  a thin  edge  to  which  the  velum 
palati  is  attached  ; its  anterior  border  is  serrated  to  join  the  palate  plate  of 
the  maxillary  bone,  its  inner  edge  rises  into  a spine  or  crest  to  support  the 
vomer,  and  is  continued  posteriorly  into  the  posterior  nasal  spine  ; its  centre 
is  thinner  than  its  edges.  The  nasal  process  or  vertical  plate  is  broad  and 
thin,  rests  partly  on  the  maxillary  bone,  its  inner  or  nasal  surface  forms  part 
of  the  nasal  fossa,  and  is  marked  by  two  depressions  which  assist  in  forming 
the  lower  and  middle  meatus  of  the  nose,  the  ridge  between  these  supports 
the  lower  spongy  bone,  externally  it  is  uneven  and  grooved  for  the  posterior 
palatine  vessels  and  nerves ; the  anterior  edge  of  this  plate  is  thin  and  brittle, 
and  prolonged  for  some  way  over  the  antrum,  the  posterior  edge  joins  the 
pterygoid  processes.  The  tuberosity  or  the  pterygoid  process  arises  from  the 
lower  and  outer  angle,  is  thick  and  wedge-shaped,  it  inclines  backwards  and 
outwards,  and  presents  three  foss®,  one  at  each  side  for  each  pterygoid  plate, 
and  one  in  the  middle  which  assists  in  forming  the  pterygoid  fossa ; the  inner- 
most of  these  fossae  is  the  deepest : this  process  is  perforated  by  one  or  two 
small  holes  which  lead  from  the  palatine  canal : at  the  upper  extremity  of  the 
nasal  plate  are  the  orbital  and  sphenoidal  processes,  separated  from  each 
other  by  a deep  notch;  the  orbital  is  the  larger  and  anterior  of  the  two,  it  is 
triangular  and  bent  a little  outwards,  it  appears  in  the  most  remote  part  of 
the  floor  of  the  orbit,  where  it  is  joined  to  the  maxillary  bone  by  one  edge,  to 
the  os  planum  by  the  second,  while  the  third  enters  into  the  spheno  maxillary 
fissure  ; the  sphenoidal  or  posterior  orbital  process  is  smaller  and  is  articu- 
lated to  the  body  and  spongy  plate  of  the  sphenoid  bone ; both  these  processes 
are  cellular,  the  cells  communicate  with  those  of  the  aethmoid  and  sphenoid 
bones ; the  notch  between  these  two  processes  forms  the  spheno  palatine  hole; 
the  palate  bone  is  joined  to  the  maxillary,  inferior  spongy,  vomer,  sphenoid, 
and  aethmoid,  and  to  the  opposite  palate  bone ; it  is  composed  of  thin  com- 
pact substance,  and  is  well  formed  in  the  foetus  ; its  processes  are  seven, 
palate,  nasal,  pterygoid,  orbital,  sphenoidal  posterior  nasal  spirae  and  crest; 


OR  MANUAL  OF  ANATOMY. 


273 


its  foramina  are  one  proper  and  two  common.  The  proper  is  the  posterior 
palatine  hole  or  holes ; the  common  are  the  posterior  palatine  or  pterygo- 
max  illary  canal  and  the  spheno-palatine  hole;  the  latter  is  above  the  nasal 
plate,  below  the  body  of  the  sphenoid,  and  between  the  orbital  processes 
of  the  palate  bone,  it  transmits  the  nasal  nerve  and  artery  from  the  spheno- 
maxillary fossa  into  the  nose. 

The  inferior  spongy  or  turbinated  bone,  placed  on  the  lower  part  of  the 
outer  side  of  the  nose,  elongated  from  before  backwards,  it  presents  a wrinkled 
or  a rugged  surface,  convex  towards  the  nose,  concave  outwards,  its  lower 
edge  is  loose,  spongy,  and  curled  outwards;  the  upper  edge  is  uneven,  thin, 
and  joined  to  the  unguis,  and  to  the  maxillary  and  palate  bones;  it  is  con- 
nected to  the  unguis  by  a thin  pyramidal  process  which  completes  the  nasal 
duct;  it  is  also  in  general  united  to  the  descending  oblique  process  of  the 
aethmoid,  it  is  composed  of  very  thin  brittle  substance  marked  with  pores  and 
little  spines. 

The  os  unguis  or  lachrymal  bone  is  placed  at  the  inner  and  fore-part  of  the 
orbit ; below  the  os  frontis,  behind  the  nasal  process  of  the  superior  maxillary 
and  before  the  aethmoid  bone,  it  is  of  an  oblong  square  shape,  and  very  thin, 
it  covers  the  anterior  ethmoidal  cells  ; externally  it  is  divided  by  a perpen- 
dicular ridge,  which  terminates  below  in  a little  hook-like  process,  into  two 
unequal  plates,  the  posterior  or  orbital  plate  is  short  and  broad,  the  anterior 
lachrymal  plate  is  concave,  long  and  narrow,  and  forms  part  of  the  lachrymal 
or  nasal  fossa  and  duct.  The  os  unguis  is  joined  above  to  the  internal  angu- 
lar and  orbitar  processes  of  the  os  frontis ; behind  to  the  os  planum  of  the 
aethmoid,  below  to  the  orbitar  plate  of  the  maxillary,  before  to  the  nasal  pro- 
cess of  the  same,  and  before  and  below  to  the  inferior  spongy  bone ; its  struc- 
ture is  very  thin  but  compact. 

The  nasal  bones  are  situated  beneath  the  nasal  process  of  the  frontal  and 
between  the  nasal  processes  of  the  superior  maxillary  bones,  they  are  small, 
narrow,  and  thick  above,  thin  and  expanded  below;  they  form  the  bridge  of 
the  nose;  the  external  surface  of  each  is  slightly  concave  from  above  down- 
wards, convex  from  side  to  side  and  perforated  with  one  or  two  small  holes ; 
the  internal  surface  is  concave  and  grooved  for  the  nasal  nerves  ; the  superior 
margin  is  thick  and  deeply  denticulated  to  join  the  nasal  process  and  spine  of  r 
the  frontal  and  the  nasal  plate  of  the  aethmoid  bones ; its  external  edge  is 
grooved  and  received  into  the  nasal  process  of  the  superior  maxillary,  its  inner 
edge  is  flat  to  join  with  its  fellow,  and  its  lower  edge  is  thin  and  irregular, 
and  joins  the  alar  cartilages  of  the  nose,  and  is  notched  for  the  passage  of  the 
nasal  branches  of  the  ophthalmic  nerve. 

The  vomer;  this  azygos  bone  resembles  a ploughshare;  it  stands  in  the 
median  line,  although  it  often  bends  a little  to  one  side,  is  thin  and  flat  and 
covered  by  the  pituitary  membrane,  it  presents  four  edges ; the  upper  or 
sphenoidal  is  hollowed  to  receive  the  azygos  process ; the  anterior  is  slightly 
grooved  to  receive  the  sethmoidal  lamina  and  the  nasal  cartilage  ; the  poste- 
rior or  pharyngeal  is  round  and  smooth  and  unattached  ; the  inferior  or  palatal 
edge  is  the  longest,  and  is  received  between  the  laminae  of  the  nasal  crest  of 
the  maxillary  and  palate  bones:  it  is  attached  to  the  maxillary,  palate,  aeth- 
moid, and  sphenoid  bones,  also  to  the  turbinated  bones  of  the  latter;  its 
structure  is  compact,  but  thin  and  transparent. 

35 


274 


THE  DUBLIN  DISSECTOR, 


The  inferior  maxillary  bone,  or  the  lower  jaw,  is  the  largest  of  the  facial 
bones,  it  is  of  a semicircular  figure  situated  at  the  lower  part  of  the  face  and 
extending  along  its  sides  and  back  part  to  the  base  of  the  skull ; it  is  divided 
into  the  body  or  chin,  the  sides,  the  rami,  and  the  processes;  the  body  is  the 
anterior  prominent  portion  with  a verticle  ridge  in  the  centre,  the  symphisis , 
or  the  line  of  union  of  the  two  symmetrical  pieces  of  which  this  bone  in 
infancy  consisted ; inferiorly  the  body  projects  into  the  mental  process  or 
chin,  above  this,  on  each  side  is  a depression  for  the  muscles  of  the  lower  lip, 
external  to  which  and  looking  backwards  is  the  oval  oblique  opening  of  the 
dental  canal,  called  the  mental  hole,  through  which  a vessel  and  nerve  of  the 
same  name  pass ; posteriorly  the  body  of  the  bone  is  concave,  and  lined  above 
by  the  mucous  membrane,  in  the  middle  it  presents  in  the  line  of  the  symphi- 
sis, a chain  of  eminences,  to  the  superior  of  which  the  frsenum  linguae 
adheres,  to  the  middle  the  genio-hyo-glossi,  and  to  the  inferior  the  genio- 
hyoidsei  muscles ; above  and  on  each  side  of  these  are  depressions  for  the 
sublingual  glands,  and  at  the  lower  border  are  two  depressions  for  the  digas- 
tric muscles.  The  sides  of  the  maxilla  have  a direction  backwards  and  out- 
wards, on  their  outer  surface  is  an  oblique  line  which  passes  backwards  and 
upwards  to  the  anterior  edge  of  the  coronoid  process,  it  gives  attachment 
before  to  theplatisma  and  depressor  anguli  oris,  and  behind  to  the  buccinator 
muscles ; internally  also  is  an  oblique  line,  parallel  to,  but  more  prominent 
than  the  external,  to  this  is  attached  the  mylo-hyoid  muscle  anteriorly,  and 
the  superior  constrictor  of  the  pharynx  posteriorly ; beneath  this  line  is  a 
slight  groove  which  contains  the  mylo-hyoid  nerve,  and  below  this  an  oblong 
depression  for  the  submaxillarv  gland ; the  lower  edge  or  base  of  the  jaw  is 
rounded,  thick  before,  thin  behind,  and  grooved  opposite  the  second  molar 
tooth  for  the  facial  artery  ; the  upper  or  alveolar  edge  is  broad  posteriorly  and 
bent  a little  inwards;  it  has  usually  16  alveoli,  which,  as  in  the  upper  jaw, 
vary  in  form  according  to  that  of  the  teeth.  The  angle  of  the  jaw  is  more  or 
less  obtuse,  and  often  bent  a little  outwards ; the  masseter  adheres  to  it  exter- 
nally, the  internal  pterygoid  internally,  and  the  stylo-maxillary  ligament  to 
the  border  of  it.  The  ramus  ascends  a little  backwards,  is  thick  and  round 
posteriorly  and  is  enveloped  by  the  parotid  gland,  externally  it  is  covered  by 
the  masseter,  internally  it  presents  a deep  groove  which  leads  to  a large  hole, 
the  inferior  dental  or  maxillary  ; this  is  situated  near  the  centre  of  the  ramus, 
and  is  protected  internally  by  a prominent  spine  into  which  the  internal  late- 
ral ligament  is  inserted,  a slight  groove  leads  from  this  hole  to  the  mylo-hyoid 
muscle ; the  dental  hole  leads  into  a canal  which  traverses  the  side  of  the  bone 
beneath  the  alveoli,  with  each  of  which  it  communicates ; it  contains  the  den- 
tal nerve  and  vessels  ; below  the  incisors  this  canal  turns  back  a little  and 
ends  at  the  mental  hole  ; this  canal  is  nearer  the  inner  surface  of  the  jaw  be- 
hind, and  the  outer  surface  before ; the  ramus  ends  above  in  a notch  and  two 
processes,  the  anterior  or  coronoid,  the  posterior  or  condyloid  ; the  notch  is 
traversed  by  the  masseter  nerve  and  vessels.  The  coronoid  process  is  trian- 
gular, the  apex  is  inclined  a little  outwards,  it  is  embraced  by  the  insertion 
of  the  temporal  muscle.  The  condyle  is  an  oblong  convex  process  supported 
bv  a neck  which  is  most  depressed  anteriorly,  for  the  insertion  of  the  external 
pterygoid  muscle;  the  condyle  is  curved  forwards  and  most  convex  in  that 
direction;  it  is  directed  obliquely  backwards  and  inwards,  so  that  its  internal 


OR  MANUAL  OF  ANATOMY, 


275 


extremity  is  posterior,  it  is  also  higher  than  the  external ; its  posterior  surface 
is  nearly  straight  and  almost  free  from  cartilage.  By  these  processes  the 
lower  maxilla  is  articulated  with  the  temporal  bones ; on  the  external  edge  of 
each  is  a tubercle  for  the  insertion  of  the  external  lateral  ligament.  The  lower 
jaw  in  the  young  subject  always  consists  of  two  symmetrical  pieces. 

The  teeth  are  small,  -hard  bones,  32  in  number,  16  in  each  jaw  ; their  form 
is  generally  conical  the  apex  in  the  alveoli  ; in  each  tooth  we  distinguish  the 
crown,  neck,  and  root ; the  crown  is  external  to  the  alveolus,  it  has  no  perios- 
teum, but  is  covered  by  a firm  white  vitreous  substance,  named  enamel : the 
neck  is  surrounded  by  the  gum,  and  the  root  is  firmly  held  in  the  alveolus  by 
a mode  of  connection  called  gomphosis.  The  teeth  are  divided  into  three 
classes,  the  incisores,  the  canini,  and  the  molares:  the  incisores  are  four  in 
each  jaw,  the  crown  of  these  is  sharp,  and  wedge-shaped,  convex  before  and 
thickly  covered  with  enamel ; those  in  the  upper  are  stronger  than  those  in 
the  lower  jaw ; the  former  are  broader,  their  edge  is  like  a chisel,  cut  off 
posteriorly,  the  latter  are  more  vertical,  their  anterior  surface  is  bevelled  off, 
but  they  are  not  so  sharp  as  those  in  the  upper  jaw,  their  roots  are  larger;  the 
the  canine  teeth  or  cuspidati  are  2 in  each  jaw,  the  crown  is  conical,  a little 
blunt,  convex  before,  their  root  is  single  but  very  long;  the  grinders  or 
molares  are  10  in  each  jaw,  the  crown  of  these  are  broad  and  irregular,  the 
roots  are  more  or  less  divided,  the  upper  grinders  are  stronger  than  the  lower, 
the  axis  of  the  former  are  directed  outwards,  in  the  latter  it  is  vertical,  the 
two  first  molar  are  called  bicuspidati,  and  are  smaller  than  the  canine ; they 
have  only  two  tubercles  on  the  crown  and  the  fang  is  single  but  sometimes  it 
is  double,  the  posterior  grinders  are  the  true  molar  or  multicuspidati,  these 
are  large ; the  crown  has  four  or  five  tubercles,  the  root  has  three  or  four 
divisions,  each  is  perforated  by  a small  hole.  The  teeth  are  composed  of  a 
very  compact  bone  or  ivory,  less  brittle  than  the  enamel ; the  latter  only  covers 
the  crown  as  far  as  the  neck ; the  ivory  has  no  cells  in  it,  its  fracture  is  silky 
in  addition  to  the  component  parts  of  bone  it  also  contains  some  fluate  of  lime: 
it  possesses  the  power  of  resisting  the  action  of  the  air  a long  time  ; the  enamel 
is  very  white  and  so  hard  as  to  strike  fire  with  steel ; it  is  composed  of  fibres 
which  are  perpendicular  to  the  surface  of  the  crown,  it  is  thicker  where  the 
teeth  are  exposed  to  much  friction,  it  does  not  contain  any  vessels  or  nerves 
and  is  not  regenerated  when  once  destroyed ; each  root  is  perforated  with  a 
small  hole  which  leads  into  the  cavity  in  the  crown ; this  cavity  contains  a 
pulp  which  is  very  vascular  and  nervous. 

The  bones  of  the  face  are  connected  by  sutures  in  the  same  manner  as  those 
of  the  cranium,  it  is  unnecessary  to  describe  these  individually,  as  they  are  all 
named  from  the  particular  bones  they  unite.  The  facial  bones,  in  addition 
to  forming  the  general  outline  of  the  face,  also  bound  several  regions,  namely, 
the  nose,  orbits,  palate,  temporal,  zygomatic  and  spheno-maxillary  fossae.  The 
bones  entering  into  the  nose  have  been  already  mentioned  in  the  description 
of  the  organs  of  sense. 

The  orbits  are  of  a pyramidal  figure,  the  base  looking  outwards  and  forwards, 
the  apex  backwards  and  inwards : 7 bones  enter  into  theparieties  of  each,  the 
frontal,  sphenoid,  lachrymal,  maxillary,  palate,  and  malar;  the  upper  wall  or 
the  roof  of  each  orbit  is  formed  by  the  frontal  and  the  lesser  wing  of  the  sphe- 
noid, it  is  concave,  and  presents  the  optic  hole  posteriorly  and  the  depressions 


276 


THE  DUBLIN  DISSECTOR, 


for  the  lachrymal  gland  and  for  the  trochlea  anteriorly ; the  floor  is  nearly 
plane  and  looks  outwards  and  downwards,  it  is  formed  of  the  malar,  maxillary, 
and  palate  bones,  the  infraorbital  canal  extends  along  it:  the  external  wall  is 
formed  by  the  sphenoid  and  malar  bones,  and  the  internal,  which  is  smooth 
and  plane,  is  formed  by  the  lachrymal,  ffithmoid,  and  sphenoid  bones.  The 
bones  which  form  the  base  of  the  orbit  are  the  frontal,  malar,  and  maxillarv, 
the  foramina  in  the  base  of  the  orbit  are  4,  viz.  the  supraorbital,  the  infraorbital, 
the  malar  and  the  nasal  duct;  within  the  orbit  are  5,  viz.  the  optic,  which  is 
in  the  upper,  inner  and  posterior  part,  the  foramen  lacerum  superius,  which 
leads  from  the  apex  upwards  and  outwards,  the  two  internal  orbital  holes  which 
are  found  in  or  close  to  the  suture  along  the  internal  wall  and  the  spheno- 
maxillary fissure,  or  the  inferior  lacerated  hole  which  leads  from  the  back  of 
the  orbit  forwards  and  outwards  along  the  floor;  this  slit-like  opening  is 
bounded  by  the  sphenoid,  palate,  maxillary,  and  malar  bones.  The  axes  of 
the  two  orbits  are  oblique  lines,  which,  if  produced  posteriorly,  would  decus- 
sate about  the  sella  turcica,  while  anteriorly  thev  would  diverge. 

The  palatine  region  is  composed  of  the  palate  plates  of  the  superior  maxil- 
lary and  of  the  palate  bones,  and  is  bounded  by  the  alveolar  arch,  by  the  ptery- 
goid processes  of  the  palate  bones  and  by  the  hamular  processes  of  the  sphe- 
noid ; to  its  posterior  edge  the  soft  palate  and  uvula  are  attached  ; anteriorly 
it  presents  the  foramen  incisivum  or  the  anterior  palatine  canal,  and  posteriorly 
the  two  posterior  palatine  canals. 

The  temporal  fossa  is  placed  on  the  side  of  the  cranium  and  face;  it  is 
bounded  internally  by  the  frontal,  sphenoid,  parietal  and  temporal  bones ; its 
extent  superiorly  is  defined  by  the  semilunar  ridge  on  the  side  of  the  cranium, 
anteriorly  by  the  malar  bone,  posteriorly  by  the  pulley -like  root  of  the  zygo- 
matic process,  and  interiorly  and  externally  by  the  zygomatic  a^ch  which  is 
formed  by  the  processes  of  that  name  from  the  temporal  and  malar  bones  ; this 
arch  is  concave  above  and  internally,  convex  below  and  externally. 

The  zygomatic  fossa  is  continuous  with  the  lower  part  of  the  last  described 
region,  from  which  it  is  distinguished  by  a transverse  ridge  or  crest  near  the 
root  of  the  great  wing  of  the  sphenoid  bone,  from  this  it  extends  to  the  tuber- 
osity of  the  maxillary  bone,  and  is  bounded  externally  by  the  ramus  of  the 
lower  jaw. 

The  ptery go -maxillary  fossa  is  a very  narrow  space,  it  is  enclosed 
between  the  pterygoid  processes  behind  and  the  tuberosity  of  the  maxillary 
bone  before,  it  is  bounded  internally  by  the  nasal  lamella  of  the  palate  bone, 
which  separates  it  from  the  nose;  it  is  immediately  below  and  behind  the 
orbit,  with  which  it  communicates  by  the  spheno  maxillary  fissure,  it  also 
communicates  with  the  palate  by  the  posterior  palatine  canals,  and  with  the 
nose  by  the  spheno  palatine  hole,  it  also  leads  into  the  temporal  and  zygomatic 
fossie. 

The  extremities  are  two  superior  and  two  inferior. 

The  inferior  extremity  is  divided  into  three  parts,  the  thigh,  leg,  and  foot; 
the  thigh  contains  but  one  bone,  the  femur. 

The  femur  is  the  longest  bone  in  the  system,  it  consists  of  the  body  or  shaft 
and  two  extremities  ; the  body  is  slightly  twisted,  thick  above,  very  broad 
below,  contracted  and  nearly  cylindrical  in  the  centre,  arched  and  smooth 
before  and  concave  behind,  with  a sharp  rough  ridge  down  the  centre,  named 


OR  MANUAL  OF  ANATOMY. 


2 77 


the  linea,  aspera  this  extends  along  the  middle  third  of  the  bone,  parallel  to 
its  axis  and  divides  above  and  below  into  two  ridges,  these  pass  superiorly  one 
to  each  trochanter,  that  to  the  inner  being  the  shorter;  and  interiorly  one  to 
either  condyle  ; these  inferior  divisions  separate  further  and  enclose  a flat  tri- 
angular space,  the  popliteal ; this  line  is  very  prominent  about  the  centre  and 
presents  two  lips  and  an  interstice,  for  tire  attachment  of  different  muscles  ; 
the  anterior  convex  surface  of  the  femur  is  broader  towards  either  end  than, 
in  the  centre,  it  is  a little  concave  superiorly,  the  sides  are  slightly  flattened, 
and  the  external  is  somewhat  broader  than  the  internal,  particularly  above  ; 
above  the  middle  of  the  linea  aspera  one  or  two  holes  may  be  seen  to  enter 
obliquely  upwards,  these  transmit  the  nutritious  or  the  medullary  vessels  of 
the  bone;  to  the  linea  aspera  in  the  middle  of  the  thigh,  the  vastus  externus, 
the  adductor  tendons,  and  the  vastus  internus  are  attached,  to  the  superior 
external  branch  which  leads  to  the  great  trochanter  and  is  very  long,  the  ad- 
ductor magnus,  gluteus  maximus,  and  vastus  externus  are  attached,  the  inter- 
nal branch  is  short  and  not  very  distinct,  it  leads  to  the  lesser  trochanter  and 
gives  attachment  to  the  adductor  brevis,  pectinaeus,  vastus  internus,  and  some 
fibres  of  the  iliacus  internus  ; to  the  lower  and  external  branch  of  the  linea 
aspera,  the  vastus  externus  and  short  head  of  the  biceps  are  attached,  and  to 
the  lower  and  internal,  the  vastus  internus  and  adductor  magnus  adhere;  these 
lines  continue  as  low  as  the  condyles,  the  internal  is  smooth  and  nearly  obli- 
terated near  its  middle  for  the  passage  of  the  crural  artery.  The  upper  or  pel- 
vic extremity  of  the  femur  presents  three  eminences,  the  head  for  articulation 
with  the  cotyloid  cavity  and  the  trochanters  for  the  insertion  of  muscles. 
The  head  is  of  a globular  figure,  and  forms  a considerable  segment  of  a 
sphere,  it  is  directed  upwards,  forwards  and  inwards  ; a little  below  its  centre 
there  is  a rough  depression  for  the  insertion  of  the  round  or  articular  ligament ; 
with  the  exception  of  this  depression  the  head  is  covered  throughout  with 
cartilage,  it  is  supported  by  an  elongated  process,  the  neck  which  forms  an 
angle,  more  or  less  obtuse,  with  the  shaft  of  the  bone,  the  direction  of  this 
process  is  upwards,  inwards,  and  a little  forwards,  it  is  flattened  before 
and  behind,  thicker  at  the  shaft  than  at  the  head,  its  lower  edge  is  longer  but 
smaller  than  the  upper ; a rough  irregular  line  separates  the  head  from  the  neck, 
beyond  which  the  articular  cartilage  does  not  extend,  and  at  its  juncture  to 
the  shaft  two  rough  lines  extend,  inwards  and  downwards,  from  the  great  to 
the  lesser  trochanter,  one  on  the  fore,  the  other  on  the  back  part  of  the  bone, 
into  these  the  capsular  ligament  is  inserted.  The  great  trochanter  is  conti- 
nuous with  the  external  side  of  the  shaft,  and  nearly  in  a line  with  its  axis,  it 
is  on  a little  lower  level  than  the  head,  it  is  thick,  rough,  and  square,  exter- 
nally it  is  broad  and  convex,  the  tendon  of  the  gluteus  maximus  moves 
over  this  surface  and  an  intervening  bursa,  a prominent  ridge  bounds 
it  below,  to  this  some  fibres  of  the  vastus  externus  are  attached,  inter- 
nally it  presents  a pit  or  digital  cavity  which  receives  the  tendons  of 
the  external  rotators  of  the  limb,  namely',  the  pyriform,  gemelli  and  obtura- 
tors ; the  summit  of  the  trochanter  is  thick  and  rough,  the  glutseus  medius  is 
inserted  into  it,  the  anterior  edge  is  broad,  and  gives  attachment  to  the  glutseus 
minimus,  into  the  posterior,  which  is  round  and  thick,  the  quadratus  femoris 
is  inserted.  The  lesser  trochanter  is  a conical  projection  at  the  posterior  and 
inner  side  of  the  shaft,  and  considerably  below  the  great  trochanter;  it  looks 


278 


THE  DUBLIN  DISSECTOR, 


backwards  and  inwards,  the  tendons  of  the  psoas  and  iliac  muscles  are  inserted 
into  it  behind  its  apex,  a bursa  is  connected  to  it  anteriorly.  The  inferior  or 
tibial  end  of  the  femur  is  very  large  and  broad,  and  divided  into  two  eminences 
or  condyles  which  are  separated  posteriorly  by  a deep  notch ; the  condyles 
articulate  with  the  tibia ; the  external  is  larger,  and  projects  more  forward  than 
the  internal,  its  articulating  surface  is  also  broader  and  ascends  higher,  exter- 
nally it  is  rough  and  presents  a tuberosity  which  gives  attachment  to  the  ex- 
ternal lateral  ligament  of  the  knee  joint;  this  is  less  prominent  than  the  internal 
tubercle,  beneath  this  tubercle  is  a groove  which  receives  the  tendon  of  the 
poplitaeus  muscle  in  the  flexed  position  of  the  joint ; internally  this  condyle 
presents  a rough  surface,  towards  the  posterior  part  of  which  the  anterior  cru- 
cial ligament  is  inserted,  it  is  very  convex  behind,  flat  before  and  broad  belowa 
The  internal  condyle  is  narrower,  less  prominent  before  but  prolonged  more 
behind  ; it  is  also  longer  than  the  external,  and  ‘herefore  descends  lower  when 
the  femur  is  vertical,  but  both  are  nearly  on  a level  when  the  bone  is  in  its 
ordinary  oblique  direction;  on  its  inner  side  is  the  tubercles  for  the  attachment 
of  the  internal  lateral  ligament  of  the  knee  and  for  the  adductor  tendon  ; to 
its  outer  side,  which  is  rough,  the  anterior  crucialligament  adheres;  both  con- 
dyles are  more  convex  behind  than  before,  they  are  separated  posteriorly  by  a 
deep  uneven  notch,  which  lodges  the  crucial  ligaments  and  is  deprived  of 
articular  cartilage;  anteriorly  they  are  continued  into  each  other,  and  unite  in 
a pulley-like  surface  which  is  convex  from  above  downwards,  and  concave  from 
side  to  side,  higher  externally  than  internally  ; this  trochlea  is  chiefly  formed 
on  the  external  condyle,  it  supports  the  patella:  the  femur  is  articulated  supe- 
riorly with  the  ilium,  interiorly  with  the  tibia  and  anteriorly  with  the  patella ; 
like  all  long  bones  it  is  composed  of  compact  tissue  in  the  centre  and  cellular 
at  the  extremities,  the  compact  has  a fibrous  appearance,  the  whole  shaft  is 
traversed  by  a distinct  medullary  canal,  which  is  crossed  by  numerous  bony 
laminse;  the  femur  is  developed  by  5 points  of  ossification,  one  for  the  shaft, 
one  for  the  tibial  end,  one  for  the  head,  and  one  in  each  trochanter. 

The  bones  of  the  leg  are  the  patella,  tibia  and  fibula. 

The  patella  or  rotula  or  knee  cap  is  a small  bone  in  front  of  the  knee  joint, 
of  a triangular  figure,  the  base  above,  the  apex  below,  its  anterior  surface  is 
convex  and  covered  by  skin,  a bursa  and  some  tendinous  fibres,  it  is  marked 
by  several  longitudinal  lines,  and  presents  a very  fibrous  appearance  ; the  pos- 
terior surface  is  covered  with  cartilage  and  divided  by  a prominent  vertical  line 
into  two  lateral  portions,  of  these  the  external  is  larger  and  deeper  than  the 
internal ; beneath  these  is  a small  triangular  depressed  surface  into  which  the 
ligament  of  this  bone  is  inserted  ; the  upper  edge  is  round  and  cut  off"  obliquely 
backwards  and  downwards,  to  it  the  extensor  tendons  are  attached  ; the  patella 
is  of  a cellular  structure  covered  by  a compact  lamina  which  is  very  dense, 
and  traversed  by  longitudinal  striae;  it  is  developed  from  a single  point  of 
ossification  and  remains  for  a long  time  cartilaginous  ; it  is  articulated  with  the 
condyles  of  the  femur,  and  connected  to  the  tibia  by  a powerlul  ligament;  it 
protects  the  fore  part  of  the  knee,  and  serves  as  amedium  of  connection  between 
the  extensor  tendon  and  the  leg. 

The  tibia , next  to  the  femur,  is  the  longest  bone  in  the  skeleton.it  occupies 
the  anterior  and  inner  part  of  the  leg,  its  upper  extremity  is  thick  and  expanded 
from  side  to  side,  its  circumference  is  somewhat  circular  or  oval,  convex  on  the 


OR  MANUAL  OF  ANATOMY. 


279 


front  and  sides,  but  slightly  grooved  behind;  on  either  side  is  a protuberance,  that 
on  the  internal  is  the  more  prominent  for  the  insertion  of  the  internal  lateral 
ligament  and  the  tendon  of  the  semi-membranosus  muscle ; a little  behind  the 
external  tuberosity  is  a small  rounded  surface  looking  downwards,  covered  with 
cartilage  for  articulation  with  the  head  of  the  fibula,  on  the  anterior  part  of  the 
head  is  a convex  triangular  surface  looking  forwards  and  downwards,  pierced 
with  many  vascular  holes,  and  terminating  in  a tubercle,  to  the  upper  part  of 
which  a bursa  adheres  and  into  the  lower  the  ligamentum  patellae  is  inserted. 
The  upper  or  femoral  surface  of  the  tibia  presents  two  concave  or  articulating 
surfaces  or  condyles  covered  with  cartilage,  for  articulating  with  the  femur,  the 
internal  is  oval  and  the  deeper  of  the  two,  it  is  also  larger  from  before  back- 
wards ; the  external  is  nearly  circular,  very  superficial,  and  looks  obliquely 
downwards  and  outwards;  these  are  separated  by  a spine,  which  is  of  a pyra- 
midal form,  inclines  upwards  and  inwards  and  is  surmounted  by  two  tubercles; 
it  is  nearer  the  back  than  the  forepart  of  the  bone;  a large  flat  depressed  surface 
lies  anterior  to  it  and  a smaller  depression  behind  it;  the  semilunar  cartilages 
and  the  crucial  ligaments  are  inserted  into  these ; the  body  of  the  tibia  is  trian- 
gular, its  size  diminishes  from  its  head  for  about  two-thirds  down,  it  then  in- 
creases somewhat  towards  its  lower  end  ; its  inner  side  is  convex  above  and  a 
little  concave  below,  it  is  directed  obliquely  forwards,  is  covered  superiorly 
by  the  tendinous  expansions  of  the  sartorius,  gracilis,  and  semi-tendinosus,  but 
the  remainder  of  it  is  subcutaneous ; the  external  side  appears  a little  twisted, 
it  is  concave  above  to  support  the  tibialis  anticus  muscle,  but  convex  below  to 
support  the  tendon  of  that  muscle  as  also  those  of  the  extensors  ; its  posterior 
surface,  which  is  also  broader  above  than  below,  is  slightly  convex  ; it  presents 
superiorly  a prominent  line  passing  obliquely  downwards  and  outwards  for 
the  insertion  of  the  poplitseus  and  the  origin  of  the  solseus  and  the  deep  flexors ; 
near  this  line  is  the  opening  of  the  large  canal  that  leads  the  vessels  to  the 
medullary  membrane,  it  slants  obliquely  downwards  and  forwards.  The  tibia 
presents  three  edges,  one  is  anterior  and  very  prominent  about  the  middle,  but 
less  so  above  and  rounded  below,  this  line  is  subcutaneous,  it  is  twisted  like 
the  tibia  itself  and  is  commonly  called  the  crest  or  the  shin,  the  inner  edge  is 
thick  and  round  and  more  distinct  below  than  above,  the  outer  edge  is  thin 
and  gives  attachment  to  the  interosseous  ligament ; it  is  less  distinct  and  bifur- 
cated below.  The  lower  or  tarsal  end  of  the  tibia  is  somewhat  square,  presents 
an  anterior  convex  edge  covered  by  the  extensor  tendons,  a posterior  nearly 
smooth  edge  traversed  by  a groove  for  the  tendon  of  the  flexor  pollicis  longus, 
externally  is  a concave  triangular  surface,  rough  above  for  ligaments,  and 
smooth  and  cartilaginous  below  to  receive  the  lower  end  of  the  fibula;  inter- 
nally the  tibia  ends  in  a thick  flattened  perpendicular  process,  the  internal 
maleolis  or  ankle ; it  is  convex  and  subcutaneous,  it  lies  anterior  to  the  superior 
internal  tuberosity  on  account  of  the  twisting  of  the  bone;  the  outer  side  of 
this  process  is  smooth  and  cartilaginous,  and  joined  at  right  angles  to  the  cavity 
at  the  lower  end  of  the  bone ; it  is  articulated  to  the  side  of  the  astragalus,  its 
anterior  edge  is  convex  and  gives  attachment  to  ligaments,  its  posterior  edge 
is  grooved  superficially  for  the  tendons  of  the  tibialis  posticus  and  flexor  com- 
munis, the  extremity  of  this  process  is  broad  and  descends  lower  before  than 
behind,  it  gives  origin  to  the  internal  lateral  ligament  of  the  ankle  ; the  lower 
surface  of  the  tibia  is  quadrilateral,  concave  from  before  backwards,  and 


£80 


THE  DUBLIN'  DISSECTOR, 


somewhat  convex  from  side  to  side,  being  traversed  from, before  backwards  by 
a very  superficial  ridge  or  prominence,  tl}is  surface  is  broader  external  v,  it 
is  bounded  internally  by  the  internal  malleolus,  and  externally  by  the  fibula; 
the  tibia  is  articulated  to  the  femur,  the  fibula  and  astragalus;  its  ossification 
commences  in  three  points,  one  for  the  shaft,  and  one  for  each  extremitv,  the 
tubercle  at  the  upper  end  of  the  crest,  and  the  malleolus  are  sometimes  found 
as  epiphyses. 

The  fibula  is  very  slender  and  nearly  as  long  as  the  tibia ; it  is  placed  at 
the  side  of  the  leg,  nearly  vertical,  its  lower  end  inclined  a little  forwards ; 
the  superior  or  femoral  end  is  small  and  circular,  and  presents  a slight  cavitv 
forwards,  upwards  and  inwards,  to  articulate  with  the  tuberosity  on  the  ex- 
ternal condyle  of  the  tibia,  behind  this  is  a slight  pyramidal  projection,  its 
whole  circumference  is  rough  for  the  insertion  of  ligaments  which  attach  it  to 
the  tibia,  also  for  the  external  lateral  ligament  of  the  knee  joint,  and  for  the 
tendon  of  the  biceps ; below  this  the  bone  is  round  and  slender  like  a neck; 
the  body  then  becomes  triangular,  is  twisted  a little  and  curved  outwards,  its 
inner  surface  looks  a little  backwards  above  but  is  twisted  forwards  below ; 
this  is  divided  into  two  portions  by  the  internal  edge  into  which  the  interos- 
seous ligament  is  inserted,  the  anterior  portion  gives  attachment  to  the  ex- 
tensors, and  the  posterior  is  grooved  for  the  tibialis  posticus,  its  external 
surface  is  covered  by  the  peronasi  muscles,  the  posterior  surface  gives  attach- 
ment to  the  solseus  above  and  to  the  flexor  pollicis  below  ; in  this  surface  we 
perceive  the  orifice  of  the  vascular  canal  leading  downwards  ; the  internal 
edge  gives  attachment  to  muscles  above  and  to  the  interosseous  ligament  below, 
the  external  edge  is  turned  backwards  and  gives  attachment  to  the  solaeus, 
flexor  pollicis,  and  peronaei  muscles ; and  the  anterior  edge  to  the  extensor 
digitorum  and  to  the  peronaei;  interiorly  this  edge  turns  outwards,  and 
bifurcates,  enclosing;  a triangular  surface,  which  is  subcutaneous  ; the  lower 
or  tarsal  end  is  larger  than  the  head,  it  is  elongated  into  a long  oval  process, 
the  external  malleolus  or  ankle,  this  is  larger,  more  prominent  and  posterior 
to  the  inner  ankle,  it  is  convex  and  subcutaneous  externally,  internally  it  is 
smooth  and  triangular,  a little  concave  from  behind  forwards  and  convex  in 
the  perpendicular  direction,  it  articulates  with  the  astragalus,  above  this  is  a 
triangular  rough  surface  to  articulate  with  the  tibia,  anteriorly  this  process  is 
rough  but  thin  for  the  origin  of  ligaments,  its  posterior  edge  is  broader  and 
grooved  for  the  peronaeal  tendons,  internal  to  which  is  a depression  for  the 
origin  of  the  posterior  lateral,  or  the  transverse  ligament  of  the  ankle  joint ; 
from  the  point  of  this  process  the  external  lateral  ligament  arises  ; the  fibula 
is  articulated  at  both  ends  to  the  tibia  and  below  to  the  astragalus. 

The  foot  is  divided  into  the  tarsus,  metatarsus,  and  toes.  The  bones  of 
the  tarsus  are  7,  astragalus,  calcaneum,  navicular,  cuboid,  and  3 cuneiform. 

The  astragalus  is  next  to  the  calcaneum  in  point  of  size,  it  is  of  an  irre- 
gular twisted  shape,  larger  above  and  to  the  outside  than  internally  or  poste- 
riorly; it  is  situated  at  the  upper  and  middle  part  of  the  tarsus,  where  it  is 
wedged  between  the  two  malleoli,  its  superior  surface  presents  in  its  two  pos- 
terior thirds  a large  pulley-like  articular  surface,  which  is  convex  from  behind 
forwards,  and  concave  transversely,  it  is  inclined  a little  backwards,  is  broader 
before  than  behipd,  and  more  prominent  externally  than  internally;  anterior 
to  this  is  a rough  depression,  on  the  neck  of  the  bone,  for  the  insertion  of 


OR  MANUAL  OF  ANATOMY. 


281 


ligaments ; interiorly,  it  presents  two  articular  surfaces  for  the  os  calcis,  one 
is  posterior  and  external,  broad  and  concave,  the  other  is  anterior  and  internal 
and  convex  ; these  surfaces  are  separated  by  a deep  groove,  which  is  narrow 
behind,  broad  before,  and  directed  forwards  and  outwards;  strong  ligaments 
pass  from  this  groove  to  the  os  calcis;  the  posterior  surface  of  the  astragulas 
is  narrow  and  slightly  grooved  in  an  oblique  direction,  downwards  and  in- 
wards for  the  tendon  of  the  flexor  pollicis ; it  presents  externally  a pointed 
eminence  to  which  the  external  lateral  ligament  of  the  ankle  joint  is  attached; 
the  anterior  extremity  is  a smooth  round  head  supported  by  a sort  of  neck,  it 
is  directed  forwards,  inwards  and  downwards,  and  is  articulated  with  the 
navicular  bone ; the  external  side  presents  a triangular,  smooth  surface, 
concave  from  above  downwards,  and  a little  convex  from  before  backwards, 
it  is  articulated  with  the  fibula;  the  inner  side  is  rough  for  ligaments,  except 
a cartilaginous  surface  near  the  upper  part,  which  is  smaller  than  that  on  the 
outer  side,  and  broader  before  than  behind,  this  is  articulated  with  the  internal 
malleolus.  f 

The  calcaneum  or  os  calcis  is  the  largest  bone  in  tire  tarsus,  at  the  lower 
and  posterior  part  of  which  it  is  placed,  it  is  elongated  posteriorly  into  a 
process  called  the  heel,  its  upper  surface  presents  two  articulating  surfaces  to 
support  the  astragalus  ; the  posterior  is  convex,  broad,  and  directed  forwards 
and  outwards,  the  anterior  is  internal,  narrow,  and  concave  ; these  are  sepa- 
rated by  a deep  rough  transverse  groove  into  which  strong  ligaments  are  in- 
serted ; internal  to  this  the  bone  is  uneven,  and  projects  into  a sort  of  process, 
into  which  the  internal  lateral  ligament  of  the  ankle  joint  is  inserted  ; the 
inferior  surface  is  smaller  than  the  superior  and  is  nearly  flat,  it  presents 
small  tubercles  for  the  attachment  of  muscles  and  ligaments:  the  posterior 
extremity  is  slightly  convex,  smooth  above  and  covered  by  a bursa,  and  rough 
below  for  the  insertion  of  the  tendo  achillis  ; the  anterior  extremity  is  smaller, 
and  presents  an  articular  surface  for  the  cuboid  bone,  which  is  concave  from 
above  downwards  and  convex  from  side  to  side;  externally  it  is  rather  flat, 
being  marked  with  two  shallow  grooves,  for  the  peronmal  tendons,  a spine 
separates  these,  into  this  the  external  lateral  ligament  of  the  ankle  joint  is 
inserted,  internally  it  is  broad  and  hollowed  out  into  an  arch,  under  which 
the  flexor  tendons,  the  tibialis  posticus  and  the  plantar  vessels  and  nerves 
pass,  the  tendon  of  the  flexor  pollicis  runs  in  a distinct  groove  ; the  os  calcis 
is  attached  above  to  the  astragalus  and  before  to  the  cuboid. 

The  navicular  or  scaphoid  bone  is  situated  about  the  middle  of  the  tarsus 
and  at  its  upper  and  internal  part ; of  an  oval  form,  its  posterior  surface  is 
smooth  and  concave,  to  form  a sort  of  superficial  or  glenoid  cavity  for  the  head 
of  the  astragulas,  the  latter,  however,  is  much  larger  and  projects  interiorly, 
in  which  direction  it  is  supported  by  the  strong  calceo-scaphoid  ligament,  and 
by  the  tendon  of  the  tibialis  posticus,  which  here  generally  contains  a sesa- 
moid bone  ; the  anterior  surface  is  convex,  and  divided  by  two  vertical  ridges 
into  three  surfaces  for  the  three  cuneiform  bones;  the  circumference  is  irre- 
gular for  the  attachment  of  ligaments,  internally  it  is  rather  smooth,  but  inte- 
riorly it  presents  a tubercle  into  which  the  tibialis  posticus  is  inserted ; on  its 
external  side  there  is  in  general  a small  flat  articular  surface  for  the  cuboid 
bone;  the  scaphoid  is  connected  to  the  astragalus,  to  the  three  cuneiform  and 
to  the  cuboid  bones 
36 


282 


THE  DUBLIN  DISSECTOR, 


The  cuboid  bone  is  situated  at  the  outer  and  anterior  part  of  the  tarsus  ex- 
ternal to  the  navicular,  and  anterior  to  the  calcaneum;  although  of  a cubical 
form,  it  is  yet  thicker  and  longer  internally  than  externally,  its  upper  surface 
is  flat  and  rough  for  the  attachment  of  ligaments  and  muscles,  the  lower  sur- 
face is  irregular,  rough  and  tubercular  behind  for  the  calceo-cuboid  ligament, 
and  groved  before  for  the  tendon  of  the  peronreus  longus,  its  posterior  surface 
is  smooth,  concave  transversely,  and  convex  from  above  downwards ; it  arti- 
culates with  the  calcaneum,  anteriorly  it  presents  two  articular  surfaces,  the 
internal  is  square  and  supports  the  fourth  metatarsal  bone,  the  external  is  tri- 
angular and  supports  the  fifth ; the  external  side  is  narrow,  the  internal  is 
rough  posteriorly  but  presents  anteriorly  two  articulating  surfaces,  the  poste- 
rior for  the  scaphoid,  and  the  anterior  for  the  external  cuneiform  bone ; the 
cuboid  is  articulated  with  the  calcaneum,  the  scaphoid,  the  external  cuneiform, 
and  the  two  external  metatarsal  bones. 

The  cuneiform  bones ; these  three  wedge-shaped  bones  are  situated  at  the 
anterior  part  of  the  tarsus,  between  the  scaphoid  and  the  three  internal  meta- 
tarsal bones;  the  first  or  the  internal  is  the  largest  of  the  three,  its  base  is  be- 
low and  its  long  axis  is  from  above  downwards,  it  is  articulated  posteriorlv  to 
the  scaphoid  bone,  anteriorly  to  the  first,  and  externally  to  the  second  meta- 
tarsal bone,  and  to  the  middle  cuneiform,  inferiorly  it  presents  a tubercle  for 
the  insertion  of  the  tibialis  anticus,  and  for  a portion  of  the  tendon  of  the 
tibialis  posticus  ; the  middle  cuneiform  is  the  smallest,  and  is  wedded  in 
between  the  two  others ; it  is  also  articulated  behind  to  the  scaphoid  and  be- 
fore to  the  second  metatarsal  bone;  the  third  or  external  cuneiform  bone  is 
situated  between  the  last  and  the  cuboid  bone,  it  is  articulated  anteriorly  with 
the  third  metatarsal  bone  ; posteriorly  with  the  scaphoid,  internally  with  the 
middle  cuneiform  and  with  the  second  metatarsal  bone,  and  externally  with 
the  cuboid,  and  with  the  fourth  metatarsal  bone.  All  the  bones  of  the  tarsus 
are  composed  of  a soft  spongy  vascular  tissue  covered  by  a compact,  but  thin 
lamina;  they  are  each  developed  from  one  point  of  ossification,  except  the 
calcaneum  and  the  astragalus,  which  commence  each  in  two  points. 

The  metatarsal  bones  are  five  in  number,  the  first  or  internal  is  the  shortest 
and  thickest,  convex  above,  concave  and  sharp  below,  its  posterior  end  is  oval, 
concave,  and  rests  on  the  internal  cuneiform  bone,  the  anterior  end  round 
and  smooth,  supports  the  first  or  great  toe,  this  extremity  is  grooved  below, 
and  lodges  the  sesamoid  bones,  the  peronreus  longus  is  also  inserted  into  it; 
the  second  is  the  longest  of  the  metatarsal  bones,  its  tarsal  end  is  wedged  in 
between  the  three  cuneiform  bones,  and  is  articulated  to  each  of  them;  the 
outer  side  of  its  base  is  also  joined  to  the  third  metatarsal  bone,  its  anterior 
extremity  or  head  is  round,  and  supports  the  second  toe,  it  is  marked  inter- 
nally and  externally  by  the  depressions  for  the  lateral  ligaments,  a groove 
separates  the  head  from  the  body  of  the  bone;  the  third  metatarsal  bone  is  a 
little  shorter  than  the  second,  but  of  the  same  form ; its  base  rests  on  the  third 
cuneiform  bone ; the  fourth  metatarsal  bone  is  a little  shorter,  it  rests  on  the 
cuboid  bone,  and  the  inner  side  of  its  base  also  rests  against  the  third  cunei- 
form bone;  the  fifth  is  the  shortest  except  the  first,  it  rests  on  the  cuboid 
bone  ; the  heads  of  all  the  metatarsal  bones  are  round,  the  bases  flat  to  articu- 
late with  the  tarsus,  the  sides  of  their  bases  are  also  flat  to  join  one  another; 
all  these  bones  possess  a similar  structure,  and  resemble  the  class  of  long 
bones. 


OR  MANUAL  OF  ANATOMY. 


£83 


The  toes  are  five  in  number,  the  first  or  the  great  toe  has  only  two  pha- 
langes, all  the  others  have  three ; there  are  therefore  fourteen  phalanges  in  all ; 
the  first  phalanges  are  longest,  they  are  convex  above,  concave  below ; their 
posterior  end  is  larger,  and  presents  a round  concavity,  for  the  head  of  the 
metatarsal  bone,  the  anterior  end  is  convex  from  above  downwards,  and  con- 
cave from  side  to  side,  so  as  to  form  a ginglymoid  joint  with  the  second  pha- 
lanx. The  second  phalanges  are  very  short,  the  great  toe  has  none,  the 
posterior  end  of  each  is  concave  from  above  downwards  but  convex  trans- 
versely, being  divided  by  a vertical  ridge ; the  anterior  extremity  is  similar  to 
that  of  the  first  phalanx,  its  condyles  are  less  prominent.  The  third  phalanges 
are  all  very  small  except  that  of  the  great  toe,  they  are  of  a pyramidal  form, 
and  support  the  nails,  their  posterior  extremity  being  very  large  and  similar 
to  that  of  the  middle  phalanges,  their  anterior  end  is  tubercular  and  attached 
to  the  cellulo-vascular  texture  at  the  extremity  of  each ; at  the  base  of  the 
first  phalanx  of  the  great  toe  there  are  in  general  two  sesamoid  bones  into 
which  the  small  muscles  of  this  toe  are  inserted,  frequently  also  there  is 
another  at  the  base  of  the  second  phalanx,  sometimes  one  is  found  at  the  first 
joint  of  the  second  toe,  and  another  at  that  of  the  fifth. 

THE  SUPERIOR  EXTREMITIES. 

Each  superior  or  thoracic  extremity  consists  of  the  shoulder  and  fore-arm, 
wrist,  and  hand ; the  shoulder  is  composed  of  the  clavicle  and  scapula,  the 
arm  of  the  humerus,  the  fore-arm  of  the  radius  and  ulna,  the  wrist  of  the 
eight  small  carpal  bones,  the  hand  of  the  five  metacarpal  and  fourteen  pha- 
langal  bones. 

The  clavicle  extends  from  the  summit  of  the  sternum  obliquely  across  the 
first  rib,  upwards,  backwards,  and  outwards  to  the  acromion  process  of  the 
scapula,  it  is  curved  somewhat  like  an  italic  S,  particularly  in  the  male,  in  the 
female  it  is  straighter  and  longer,  it  consists,  like  all  long  bones,  of  two  extre- 
mities and  a body  or  shaft;  the  internal  or  sternal  end  is  thick,  it  presents  a 
triangular  articulating  surface,  inclined  forwards  anil  downwards,  convex  from 
above  downwards,  concave  from  before  backwards,  large  above  and  before, 
small  and  pointed  below  and  behind,  the  circumference  is  rough  for  the  attach- 
ments of  ligaments  ; the  body  is  nearly  cylindrical  towards  the  sternal,  but  flat 
and  expanded  towards  the  acromial  end,  smooth  above  and  mostly  subcutaneous, 
interiorly  it  is  rough,  and  presents  about  an  inch  from  the  sternal  end,  a ridge 
or  process  for  the  rhomboid  ligament,  external  to  this  is  a groove  for  the  subcla- 
vian muscle,  in  which  is  a foramen  for  the  nutritious  vessels,  and  near  the  sca- 
pular end  is  a rough  ridge  leading  backwards  and  outwards  for  the  attachment 
of  the  coraco-clavicular  ligaments ; its  anterior  edge  is  convex  in  the  inner  half, 
and  gives  attachment  to  the  great  pectoral  muscle  ; the  outer  half  is  concave, 
the  deltoid  is  attached  to  it;  the  posterior  is  smooth  and  concave  in  the  inner 
half  towards  the  great  vessels,  and  rough  and  convex  externally  for  the  attach- 
ment of  the  trapezius  muscle;  the  acromial  end  of  the  clavicle  passes  over  the 
coracoid  process  upwards  and  backwards,  is  flat  and  broad,  rough  above  and 
below,  and  perforated  by  vessels  ; it  presents  at  its  termination  a small  arti- 
culating surface  for  the  acromion  scapulae ; this  surface  is  oval  from  before 
backwards,  and  cut  obliquely  from  above  and  from  without  downwards  and 


284 


THE  DUBLIN  DISSECTOR, 


inwards,  its  aspect  is  outwards,  forwards  and  downwards,  its  circumference 
is  rough  for  the  attachment  of  ligaments;  the  clavicle  serves  to  support  the 
scapula  and  to  prevent  it  from  falling  too  much  forwards  or  inwards, it  thereby 
allows  it  a greater  freedom  of  motion,  it  also  serves  as  a fixed  point  for  cer- 
tain muscles,  and  it  protects  the  vessels  and  nerves  of  the  upper  extremity ; it 
is  very  perfect  in  the  foetus,  and  is  developed  from  a single  point  of  ossifica- 
tion ; it  has  no  perfect  epiphysis,  although  in  the  young  subject  there  is  an 
osseous  crust  at  each  extremity,  which  is  at  first  separable  from  the  rest  of  the 
bone. 

The  scapula  is  situated  at  the  upper,  lateral,  and  posterior  part  of  the  chest, 
and  extends  from  the  second  to  the  seventh  rib,  it  is  irregularly  flat  and  trian- 
gular, it  presents  an  internal  and  an  external  surface,  three  edges  and  three 
angles ; the  internal  or  anterior  surface  or  subscapular  fossa  looks  towards  the 
ribs,  is  slightly  concave  and  divided  by  three  or  four  prominent  lines  which 
run  obliquely  from  above  downwards,  and  from  without  inwards  into  several 
broad  grooves,  which  are  filled  by  the  fasciculi  of  the  subscapular  muscle,  the 
apoueurosis  of  which  is  attached  to  those  ridges  ; above  and  below  these  is  a 
smooth  flat  surface  to  which  the  serratus  magnus  is  attached  ; the  external  or 
posterior  surface  or  the  dorsum  is  divided  transversely  into  two  unequal  parts 
by  a ridge  or  spine  which  commences  at  the  posterior  border  of  the  scapula, 
from  a smooth  polished  flat  triangular  surface,  it  proceeds  forwards  and  be- 
comes more  elevated,  flattened  above  and  belowr,  and  bounded  by  long  irregu- 
lar undulated  margin,  which  is  rough  above  for  the  attachment  of  the  trapezius, 
and  below  for  that  of  the  deltoid  muscle  ; a vascular  hole  is  observed  on  its 
upper  and  under  surface;  this  spine  is  a little  contracted  anteriorly  and  ex- 
ternally, and  terminates  in  an  eminence  named  the  acromion  process ; this 
surmounts  the  shoulder  joint,  about  an  inch  above  it  is  flattened  in  a direction 
contrary  to  that  of  the  spine,  its  external  surface  looks  a little  upwards  and 
backwards,  is  convex,  rather  rough  and  covered  by  the  integuments,  its  infe- 
rior or  internal  surface  is  smooth  and  concave,  its  upper  edge  is  directed  back- 
wards, gives  attachment  to  the  trapezius  and  presents  near  its  termination  a 
small  oval  articulating  surface  for  the  clavicle;  the  lower  edge  gives  attach- 
ment to  the  deltoid,  its  apex  its  rounded  for  the  insertion  of  the  triangular  or 
coraco-acromial  ligament ; above  this  spine  is  the  supra-spinata  fossa,  which 
is  wider  behind  than  before,  this  is  filled  by  the  supra-spinous  muscle  the  fossa 
infra-spinata  is  larger,  is  convex  above  and  concave  and  grooved  inferiorly; 
between  this  and  the  inferior  costa  is  a raised  surface  extending  from  the  infe- 
rior angle  to  the  glenoid  cavity  ; this  surface  is  divided  into  two  by  an  oblique 
line,  the  posterior  portion  is  flat  and  somewhat  square,  and  gives  attachment 
to  the  teres  major  muscle,  the  anterior  to  the  teres  minor;  into  the  ridge 
between  these  is  inserted  an  aponeurosis  common  to  these  two  muscles;  the 
superior  or  cervical  costa  or  border  of  the  scapula  is  the  shortest  and  thinnest ; 
at  its  fore-part  is  a notch  which  is  converted  into  a hole  by  ligament  and  some- 
times by  bone  ; it  is  traversed  by  the  supra-scapular  nerve,  and  sometimes  by 
the  vessels  of  that  name,  to  this  costa,  the  supra-spinatus,  subscapular,  and  omo- 
hoid  muscles  are  attached  ; from  the  anterior  part  of  this  border  in  front  of 
the  notch  arises  the  coracoid  process , which  is  long  and  narrow,  and  directed 
at  first  upwards  and  forwards  and  then  downwards,  convex  and  rough  above 
for  the  attachment  of  the  coracoid  and  trapezoid  ligaments,  smooth  and 


OR  MANUAL  OF  ANATOMY. 


285 


concave  below,  it  overhangs  the  inner  and  upper  part  of  the  glenoid  cavity,  the 
■pectoralis  minor  is  inserted  into  it  anteriorly,  the  biceps  and  coraco-brachialis 
into  its  summit,  and  the  triangular  ligament  into  its  external  border.  The 
base  of  the  scapular  or  the  posterior  or  vertebral  edge  is  nearer  the  spine  above 
than  below  ; the  spinati  muscles  adhere  to  its  outer  lip,  the  subscapular  to  its 
inner,  and  the  rhomboid  to  its  middle  ; about  one  fourth  from  its  upper  extre- 
mity is  a blunt  projection  formed  .by  the  smooth  triangular  root  of  the  spine ; at 
the  union  of  the  base  and  upper  costa  is  the  superior  posterior  angle,  which  is 
embraced  by  the  levator  anguli  muscle.  The  anterior  or  inferior  or  external 
or  axillary  costa  is  very  thick  and  inclines  downwards  and  forwards,  at  its 
junction  with  the  base  it  forms  the  inferior  angle  on  which  is  a long  flat  sur- 
face which  gives  origin  to  the  teres  major,  and  to  a few  fibres  of  the  lattisimus 
dorsi  muscle  ; to  the  upper  part  of  it  the  long  head  of  the  triceps  is  attached; 
at  the  convergence  of  this  and  the  superior  costa,  the  glenoid  cavity  and  the 
neck  of  the  scapula  are  situated.  The  neck  is  that  contracted  portion,  which 
gives  attachment  to  the  capsular  ligament,  it.  is  most  distinct  externally  and 
interiorly.  The  glenoid  cavity  is  superficial,  oval,  broader  below,  covered 
with  cartilage,  and  in  the  recent  subject  deepened  by  the  fibrous  glenoid  liga- 
ment, which  is  chiefly  derived  from  the  long  tendon  of  the  biceps,  which  is 
attached  to  the  upper  extremity  of  the  cavity;  it  is  inclined  a little  downwards, 
outwards,  and  forwards, ; its  aspects  however  varies,  as  the  scapula  is  made 
to  turn  in  all  the  rotatory  motions  of  the  arm.  The  scapula  is  composed  of 
two  compact  laminae,  and  an  intervening  cellular  tissue,  the  latter  prevails  in 
the  processes,  the  neck  and  the  inferior  angle ; in  the  middle  of  the  fossae  there 
is  but  little  of  it,  and  the  compact  substance  is  there  thin  and  transparent. 
The  scapula  is  developed  by  several  points  of  ossification,  one  in  the  centre 
of  the  body,  one  for  each  of  the  processes,  one  for  the  inferior  angle,  and  one 
for  the  posterior  or  vertebral  edge. 

The  os  humeri  is  attached  to  the  scapula  above  and  to  the  radius  and  ulna 
below  ; it  is  the  longest  and  largest  bone  in  the  upper  extremity,  it  presents 
two  extremities  and  a body  or  shaft ; the  upper  or  scapular  extremity  is  the 
larger,  and  consists  of  the  head,  neck,  and  2 tubercles.  The  head  is  semi- 
spherical,  inclined  upwards, inwards,  and  backwards,  smooth  and  covered  with 
cartilage  for  articulating  with  the  glenoid  cavity  of  the  scapula;  the  neck  is 
the  slightly  contracted  line  around  the  head;  it  is  rough  for  the  attachment 
of  the  capsular  ligament,  and  a little  longer  below  and  before  than  above  or 
behind;  the  axis  of  the  neck  and  head  forms  an  obtuse  angle  with  that  of  the 
shaft ; the  tuberosities  are  two,  the  greater  and  lesser  ; the  great  or  external 
is  also  posterior,  it  is  round,  and  presents  three  depressions ; to  the  anterior 
of  these  the  supra-spinous  muscle  is  attached,  totiie  middle  the  infra-spinous, 
and  to  the  posterior  the  teres  minor  ; the  lesser  tuberosity  is  also  anterior ; it 
is  more  prominent,  and  gives  insertion  to  the  subscapsular  tendon  ; between 
these  tubercles  is  the  deep  groove  for  the  long  tendon  of  the  biceps,  into  the 
anterior  edge  of  which  the  tendon  of  the  great  pectoral  is  inserted,  and  into  its 
posterior  those  of  the  teres  major  and  latissimus  dorsi,  this  groove  leads  down- 
wards and  inwards.  The  body  or  shaft  of  the  humerus  is  thick  and  round 
above,  twisted  in  the  middle,  expanded  and  somewhat  triangular  inferiorly; 
its  posterior  surface  is  round  above  and  twisted  a little  inwards,  below  it  looks 
outwards  and  is  flat  and  broad ; this  surface  is  covered  by  and  gives  attachment 


286 


THE  DUBLIN  DISSECTOR, 


to  the  triceps  muscle,  a small  vascular  foramen  may  be  observed  about 
the  centre ; the  anterior  surface  is  divided  for  about  one-fourth  of  its  length 
by  the  bicipital  groove  into  two  unequal  portions,  the  internal  of  which* is 
smooth,  and  presents  near  its  centre  a linear  elevation  for  the  insertion  of  the 
coraco-brachialis,  in  the  lower  part  of  which  is  an  oblique  vascular  foramen; 
the  external  portion  is  rough  above  for  the  insertion  of  the  deltoid  muscle,  and 
is  grooved  obliquely  below  for  the  passage  of  the  musculo-spiral  nerve  and 
artery ; these  surfaces  are  separated  by  two  prominent  lines,  one  is  external 
and  anterior,  the  other  is  internal  and  posterior,  these  lines  are  more  distinct 
below  than  above,  they  give  attachment  to  the  intermuscular  ligaments  and 
lead  down  to  either  condyle,  the  external  is  interrupted  about  the  middle  by 
the  musculo-spiral  groove,  but  is  very  prominent  below,  curved  forwards  and 
gives  attachment  to  the  brachiaeus  anticus,  the  supinators  and  extensors,  the 
triceps  and  the  external  intermuscular  ligament;  on  the  anterior  surface  of 
the  humerus  there  is  also  a prominent  line  continued  from  the  anterior  edge 
of  the  bicipital  groove,  it  is  gradually  flattened  below  and  covered  bv  the 
brachiaeus  anticus  muscle.  The  lower  extremity  of  the  humerus  is  flattened, 
elongated  transversely  and  twisted  a little  forwards,  it  presents  internally 
the  internal  condyle  which  is  very  prominent  and  turned  somewhat  backwards, 
this  gives  attachment  to  the  common  tendon  of  the  pronators  and  flexors,  and 
to  the  internal  lateral  ligament  of  the  elbow  joint,  externally  is  the  external 
condyle,  not  so  prominent  as  the  internal,  and  situated  lower  down,  it  gives 
attachment  to  the  external  lateral  ligament,  and  to  the  supinator  and  extensor 
muscles;  between  these  condyles  is  an  articulating  surface  turned  forwards 
and  presenting  externally  a small  round  head  which  articulates  with  the  radius, 
above  and  internal  to  which  is  a slight  depression  corresponding  to  the  margin 
of  the  radius,  internal  to  this  is  a sharp  semicircular  ridge  which  separates  the 
radius  and  ulna,  and  next  to  this  is  the  trochlea  for  articulation  with  the  ulna, 
this  is  so  much  below  the  level  of  the  small  head  and  of  the  outer  portion  ot 
the  articular  surface,  as  to  give  the  whole  bone  an  oblique  direction  outwards 
when  its  lower  end  is  placed  on  a horizontal  plane  ; at  the  anterior  extremity 
of  this  trochlea  is  a small  depression  for  the  reception  of  the  coronoid  process 
in  flexion  of  the  joint,  and  at  the  posterior  is  a large  fossa  which  lodges  the 
olecranon  process  in  the  extended  state.of  the  forearm.  The  humerus,  like 
the  femur,  is  compact  in  the  structure  of  its  body,  and  cellular  in  that  of  its 
extremities,  it  contains  a large  medullary  canal,  and  is  developed  from  eight 
points  of  ossification,  one  for  the  head,  one  for  each  tuberosity,  one  for  the 
•shaft,  one  for  the  trochlea,  one  for  the  small  head,  and  one  for  each  condyle. 

The  ulna  is  situated  at  the  inner  side  of  the  forearm,  it  is  longer  than  the 
radius,  and  is  divided  into  the  body  and  two  extremities ; the  upper  extremity 
is  larger  than  the  lower,  and  presents  two  processes  and  an  intervening  cavity ; 
the  posterior  process,  or  the  olecranon,  is  the  highest  part  of  the  bone,  its  supe- 
rior border  gives  attachment  to  the  triceps  extensor,  posteriorly  it  presents  a 
■smooth  triangular  surface,  covered  by  skin  and  by  a bursa  ; anteriorly  it  is 
concave,  and  covered  with  cartilage  ; the  coronoid  process  is  anterior  and  infe- 
rior to  the  preceding;  anteriorly  it  gives  insertion  to  the  brachialis  anticus 
muscle,  internally  to  the  flexors  and  pronators,  and  to  the  internal  lateral 
ligament;  and  externally  it  is  hollowed  out  into  the  lesser  sigmoid  cavity, 
which  receives  the  head  of  the  radius ; this  cavity  is  oval,  its  greatest dian  eter 


OR  MANUAL  OF  ANATOMY. 


287 


being  from  before  backwards,  itleads  superiorly  into  the  great  sigmoid  cavity , 
which  moves  on  the  trochlea  of  the  humerus  in  flexion  and  extension  of  the 
forearm;  this  sigmoid  cavity  has  a great  resemblance  to  the  letter  e,  if  viewed 
in  profile ; it  is  covered  with  cartilage ; its  posterior  vertical  portion  is  larger 
than  the  anterior  horizontal ; it  is  divided  by  a middle  ridge  into  two  lateral 
portions,  of  which  the  internal  is  the  larger ; these  are  each  again  divided  by 
a transverse  furrow,  which  ends  in  a notch  at  either  margin.  The  body  of 
the  ulna  is  divided  into  three  surfaces  by  three  lines  ; these  surfaces  are  larger 
above  than  below  ; the  anterior  is  slightly  grooved  for  the  flexor  profundus, 
and  presents  superiorly  a vascular  foramen,  directed  obliquely  upwards  ; the 
interna^  surface  is  broad  and  concave  above,  and  covered  by  muscles,  below 
it  is  round  and  subcutaneous  ; the  posterior  surface  is  irregular  ; it  is  divided 
into  two  portions  by  a prominent  line ; of  these  the  superior  and  internal  is 
broad,  and  gives  attachment  to  the  anconseus;  the  inferior  and  outer  portion 
is  long  and  narrow,  and  covered  by  the  extensors  of  the  thumb  ; the  anterior 
edge  is  round,  and  gives  insertion  to  the  flexor  profundus  and  pronator  quad- 
ratus;  the  posterior  edge  is  very  distinct  above,  and  gives  attachment  to  an 
aponeurosis,  common  to  the  flexor  profundus  and  flexor  and  extensor  carpi 
ulnaris ; the  external  edge  is  sharp  for  the  three  superior  fourths,  and  gives 
attachment  to  the  interosseous  ligament.  The  lower  or  carpal  end  of  the  ulna 
is  small  and  round,  and  presents  two  eminences  ; the  external  is  named  the 
head,  it  Is  round,  and  covered  with  cartilage,  and  is  received  into  the  cavity  in 
the  inner  border  of  the  radius,  and  is  contiguous  inferiorly  with  the  fibro  car- 
tilage of  the  wrist;  the  internal  eminence  or  the  styloid  process  is  more  pro- 
minent, and  on  a level  with  the  posterior  surface  of  the  bone  ; it  is  conical, 
elongated,  and  a little  everted ; it  gives  attachment  to  the  internal  lateral 
ligament  of  the  wrist ; these  processes  are  separated  posteriorly  by  a groove 
for  the  tendon  of  the  extensor  carpi  ulnaris,  and  inferiorly  by  a depression  for 
the  insertion  of  the  triangular  fibro  cartilage.  The  ulna  is  articulated  above 
to  the  humerus  and  radius,  and  below  to  the  radius  and  interarticular  cartilage ; 
it  is  developed  from  three  points  of  ossification,  one  for  the  shaft,  and  one  for 
each  extremity. 

The  radius  is  shorter  then  the  ulna  by  the  length  of  the  olecranon  ; it  is 
situated  at  the  outer  and  anterior  part  of  the  forearm,  is  larger  below,  than 
above,  is  curved  about  the  centre,  and  is  convex  outwards ; it  is  divided  into 
the  body  and  two  extremities ; the  upper  or  humeral  end  presents  ahead,  neck, 
and  tubercle  ; the  head  is  a circular  superficial  cavity,  its  surface  and  circum- 
ference covered  with  cartilage  ; the  former  to  articulate  with  the  small  head  of 
the  humerus,  and  the  latter  with  the  sigmoid  cavity  of  the  ulna,  and  with  the 
annular  or  coronary  ligament ; the  internal  or  ulnar  portion  of  the  circumference 
is  broader  than  the  external ; the  neck  is  about  an  inch  long,  it  descends  obliquely 
outwards,  it  is  contracted  and  circular  ; at  its  lower  extremity  is  the  tubercle 
this  process  is  directed  backwards  and  inwards,  into  its  external  rough  surface 
the  tendon  of  the  biceps  is  inserted  ; anterior  it  is  smooth,  and  covered  by  a 
bursa.  The  bo dy  or  shaft  of  the  radius  is  somewhat  triangular,  and  presents 
three  surfaces,  separated  by  three  margins  or  angles;  the  anterior  surface  is 
broad  below  and  covered  by  the  pronator  quadratus,  narrow  above  where  it 
gives  attachment  to  the  flexor  pollicis  ; about  one-third  from  the  head  is  the 
orifice  of  the  vascular  canal,  slanting  obliquely  upwards ; the  posterior  surface 


288 


THE  DUBLIN  DISSECTOR, 


is  convex  above  and  covered  by  the  supinator  brevis,  concave  in  the  middle  for 
the  extensors  of  the  thumb,  and  convex  below  ; the  external  surface  is  round 
and  convex,  and  presents  near  the  centre  a rough  surface  for  the  insertion  of 
the  pronator  teres  ; of  the  angles  or  edges  the  inner  is  most  distinct ; it  is  sharp, 
and  gives  attachment  to  the  interosseous  ligament.  The  lower  or  carpal  end 
of  the  radius  is  square,  its  anterior  prominent  edge  gives  attachment  to  the  ante- 
rior carpal  ligament ; posteriorly  it  presents  three  grooves  for  the  extensor 
tendons  ; one  nearly  in  the  middle  line,  narrow  and  oblique,  lodges  the  tendon 
of  the  extensor  secundi  internodii  pollicis,  the  second  is  at  the  ulnar  side  of 
this,  is  broad,  and  transmits  the  tendons  of  the  extensor  communis  and  indicator 
and  the  third,  which  is  to  the  radial  side  of  the  first,  is  divided  into  two  for 
the  tendons  of  the  extensor  carpi  radialis,  longus,  and  brevis  ; along  the 
external  border  of  these  bone,  is  another  groove  leading  downwards  and  for- 
ward and  divided  into  two  for  the  extensor  ossis  metacarpi  and  primi  internodii 
pollicis  ; the  border  between  these  two  last  grooves  is  prolonged  down  into 
the  styloid  process,  from  which  the  external  lateral  ligament  of  the  wrist  arises; 
on  the  internal  border  is  an  oblong  smooth  cavity,  to  receive  the  lower  end  of 
the  ulna  ; inferiorly  the  radius  presents  an  articular  surface,  divided  bva  line 
from  before  backwards,  into  two  unequal  portions  ; the  external  is  large  and 
triangular,  and  meets  the  scaphoid  bone ; the  internal  is  smaller,  somewhat 
square,  and  meets  the  lunar  bone.  The  radius,  like  other  long  bones,  is  of  a 
cellular  structure  at  each  extremity,  and  compact  in  the  centre,  where  it  also 
contains  a medullary  canal,  which  is  larger  above  than  below  ; it  is  developed 
from  three  points  of  ossification,  one  for  the  shaft  and  one  for  each  extremity. 

The  hand  consists  of  the  carpus,  metacarpus,  and  fingers. 

The  carpus  is  composed  of  8 bones,  arranged  in  two  rows ; the  first  rovj 
consists  of  the  scaphoid,  lunar,  cuneiform,  and  pisiform  ; the  second  of  the 
trapezium,  trapezoid,  magnum,  and  unciform,  enumerating  them  from  the 
radial  to  the  ulnar  side,  or  from  without  inwards. 

The  scaphoid  is  the  largest  in  the  upper  row,  at  the  upper  and  outer  side  of 
which  it  is  situated  ; it  presents  four  articular  surfaces  ; it  is  elongated  and 
convex  on  the  upper  or  radial  surface,  adapted  to  the  external  depression  on 
the  end  of  the  radius ; the  inferior  surface  directed  a little  outwards  and 
backwards,  is  triangular,  smooth,  and  convex,  to  articulate  with  the  trapezium 
and  trapezoides ; into  the  posterior  narrow  surface,  ligaments  are  inserted; 
to  the  external  or  radial  side,  the  external  lateral  ligament  is  attached  ; the 
inner  or  ulnar  side  presents  two  smooth  articulating  surfaces  ; one  superior, 
narrow,  to  articulate  with  the  lunar  bone  ; the  other  inferior,  large  and  con- 
cave, to  articulate  with  the  magnum. 

The  semicircular  or  lunar  hone  is  smaller  than  the  scaphoid  ; it  presents 
four  articulating  surfaces;  smooth  and  convex  above  to  meet  the  radius,  con- 
cave below  to  articulate  with  the  magnum  and  unciform;  its  ulnar  side  is  flat 
to  meet  the  cuneiform,  and  its  external  to  meet  the  scaphoid  ; its  anterior 
surface  is  larger  than  its  posterior,  and  it  projects  a litttle  into  the  palmar 
arch . 

The  cuneiform,  or  pyramided  hone.  The  .base  of  this  wedge-shaped  bone 
looks  outwards,  and  articulates  with  the  lunar,  the  apex  inwards ; it  is  convex 
and  smooth  above  to  meet  the  carpal  fibro-cartilage ; concave  and  smooth 
below  to  articulate  with  the  unciform  bone;  rough  posteriorly  and  internally 


OR  MANUAL  OF  ANATOMY. 


289 


for  ligaments ; anteriorly  it  presents  a flat  circular  cartilaginous  surface  for 
the  pisiform  bone. 

The  pisiform  bone.  This  small  pea-shaped  bone  is  the  smallest  in  the 
carpus,  at  the  upper  and  inner  part  of  which  it  is  placed  ; it  is  also  on  a plane 
anterior  to  the  flrst  row ; it  is  articulated  to  the  cuneiform  bone  by  a small 
circular  surface;  its  circumference  is  rough  for  the  attachment  of  ligaments; 
the  flexor  carpi  ulnaris  is  inserted  into  it  above,  and  the  abductor  minimi  digiti 
below. 

The  trapezium  is  the  most  external  of  the  second  row  of  the  carpus  ; it  is 
concave  above  to  meet  the  scaphoid,  below  it  is  convex  from  behind  forwards, 
and  concave  transversely,  to  support  the  metacarpal  bone  of  the  thumb; 
anteriorly  it  is  marked  with  a groove  for  the  tendon  of  the  flexor  carpi  radialis; 
internally  it  is  articulated  to  the  trapezoid,  and  beneath  this  by  a small  surface 
to  the  second  metacarpal  bone. 

The  trapezoid  is  of  a very  irregular  shape,  and  smaller  than  the  trapezium  ; 
above  it  is  smooth  and  concave  to  meet  the  scaphoid,  externally  it  articulates 
with  the  trapezium,  internally  with  the  magnum,  and  inferiorly  with  the 
second  metacarpal  bone. 

The  os  magnum  is  the  largest  of  the  carpal  bones ; it  presents  superiorly  a 
round  and  hemispherical  head,  which  is  received  into  the  socket  formed  by  the 
scaphoid  and  lunar  bone's;,  this  head  is  supported  by  a contracted  neck,  its 
greatest  convexity  is  turned  backwards  and  outwards;  the  inferior  surface  of 
the  magnum  is  divided  into  three  articulating  surfaces;  these  support  the  2d, 
3d,  and  4th  metacarpal  bones;  that  for  the  3d  is  the  largest;  its  posterior 
surface  is  broad  and  convex  below,  and  a little  concave  above;  externally  it 
joins  the  trapezoid,  and  internally  the  unciform  ; both  anteriorly  and  poste- 
riorly it  gives  attachment  to  the  ligaments. 

The  unciform  bone  is  next  in  size  to  the  os  magnum  ; it  is  situated  at  the 
lower  and  inner  part  of  the  carpus,  is  rather  wedge-shaped,  the  base  below, 
articulated  with  the  4th  and  5th  metacarpal  bones ; its  upper  surface  is  narrow, 
and  meets  the  semilunar  bone ; its  external  side  joins  the  magnum,  its  internal 
the  cuneiform;  its  posterior  surface  is  rough  for  ligaments;  from  its  anterior 
projects  a small  hooked  process,  curved  outwards  for  the  attachment  of  the 
annular  ligament  and  some  of  the  muscles  of  the  little  finger.  All  the  bones 
ot  the  carpus,  like  those  of  the  tarsus,  are  composed  of  a loose  spongy  vascular 
tissue,  invested  by  a thin  compact  lamina;  they  are  developed  each  from  a 
single  point  of  ossification,  except  the  unciform,  which  has  two;  the  pisiform 
is  the  latest  to  ossify. 

The  metacarpal  bones  belong  to  the  class  of  long  bones  ; they  are  5 in  num- 
ber, are  placed  nearly  parallel  to  each  other,  except  the  first,  which  is  on  a 
plane  anterior  to  the  others  ; the  1st  is  thick  and  short,  the  3d  is  the  longest. 
They  are  all  concave  on  the  palmar  surface,  convex  on  the  dorsal,  and  large 
at  each  extremity ; the  posterior  end  is  of  an  irregular  figure;  the  anterior 
presents  a round  head  ; the  palmar  surface  of  each  is  narrow,  and  presents  a 
median  prominent  line  ; the  posterior  surface  of  the  1st  is  convex,  but  on  the 
2d,  3d  and  4th,  it  presents  a prominent  longitudinal  line,  which  bifurcates  and 
iorrps  the  sides  ot  a flat  triangular  surface,  extending  for  near  two-thirds  of 
their  length  ; into  their  edges  the  interosstei  muscles  are  inserted  ; the  dorsal 
surface  of  the  5th  is  divided  by  an  oblique  line  diagonallv,  the  outer  portion 
37 


290 


THE  DUBLIN  DISSECTOR, 


is  concave,  and  lodges  the  fourth  interosseous  muscle,  the  inner  convex  and 
broad,  and  covered  by  the  extensor  tendon  of  the  little  finger.  The  carpal 
end  or  base  of  the  1st  is  concave  from  before  backwards,  and  convex  trans- 
versely, to  articulate  with  the  trapezium  ; the  base  of  the  2d  is  concave,  and 
articulates  with  the  trapezoides,  and  presents  externally  a small  smooth  surface 
for  the  trapezium,  and  internally  two  smooth  surfaces,  one  for  the  magnum, 
the  other  for  the  base  of  the  3d  metacarpal ; the  base  of  the  3d  is  nearly  plane, 
and  rests  on  the  magnum,  and  presents  on  either  side  articulating  surfaces  for 
the  contiguous  metacarpal  bones ; the  base  of  the  4th  presents  two  articulating 
surfaces,  one  for  the  magnum  and  one  for  the  unciform  ; on  the  radial  side 
two,  and  on  the  ulnar  side  one  articulating  surface,  for  the  adjacent  metacarpal 
bones;  the  base  of  the  5th  presents  a concave  surface,  directed  outwards  to 
articulate  with  the  unciform  ; its  radial  side  articulates  with  the  base  of  the 
4th  metacarpal  bone.  The  anterior,  or  digital  ends  of  all  the  metacarpal 
bones  are  convex,  their  smooth  surfaces  extending  further  on  the  palmar  than 
on  the  dorsal  surfaces  of  each  ; they  are  articulated  with  the  bases  of  the  first 
phalanges. 

The  fingers  are  composed  each  of  three  phalanges,  except  the  thumb, 
which  has  only  two ; there  are  therefore  14  phalanges  in  all ; the  first,  or  those 
next  the  metacarpus,  are  the  largest,  the  third  are  the  smallest,  the  2d  or 
middle  are  of  an  intermediate  size.  The  metacarpal,  or  the  first  phalanges 
are  5 in  number ; the  base  or  posterior  end  of  each  presents  an  oval  cavity  for 
the  head  of  the  metacarpal  bone  ; the  anterior  extremity  of  each  presents  two 
small  condyles,  separated  by  a groove;  these  are  prolonged  anteriorly,  and 
articulate  with  the  second  or  middle  phalanx;  the  anterior  surface  of  each  is 
arched  from  before  backwards,  hollowed  from  side  to  side,  to  lodge  the  flexor 
tendon,  the  sheath  of  which  is  attached  to  its  lateral  edges;  the  posterior 
surface  is  convex  and  arched.  The  second  or  middle  phalanges  are  4 in  num- 
ber, they  are  smaller  than  the  first ; the  base  of  each  presents  a pulley-like 
surface  to  articulate  with  the  first,  with  which  it  forms  ginglymoid  joint ; about 
the  centre  of  their  anterior  surface  is  a rough  depression  for  the  insertion  of 
the  tendon  of  the  flexor  sublimis;  the  anterior  or  digital  extremity  of  each 
resembles  the  anterior  end  of  the  first  phalanx,  and  is  convex  from  before 
backwards,  and  concave  from  side  to  side  ; the  two  articulating  condyles  being 
prolonged  on  the  palmar  further  than  on  the  dorsal  surface,  so  as  to  increase 
the  extent  of  flexion;  the  thumb  wants  this  second  phalanx.  TheMtrdor 
last  or  ungual, phalanges  are  five  in  number,  they  are  the  smallest,  somewhat 
of  a pyramidal  form  ; the  base  articulates  with  the  2d  phalanx,  and  presents  a 
pulley-like  surface,  having  two  small  cavities  and  a middle  ridge,  such  as  the 
base  of  the  2d  phalanx ; their  posterior  surface,  convex,  supports  the  nail,  their 
anterior  rough  and  irregularly  concave,  for  the  attachment  of  the  flexor  tendon 
and  ligaments;  its  anterior  extremity  or  apex  is  irregularly  tuberculated  to 
support  the  extremity  of  the  finger.  The  phalanges  in  structure  resemble 
metacarpal  bones;  the  last  are  more  cellular,  and  have  no  medullary  canal ; 
they  are  developed  each  from  two  points  of  ossification,  one  for  the  shatt.  and 
one  for  the  anterior  extremity  ; the  posterior  end  is  continued  trom  the  shatt 
On  the  articulation  between  the  metacarpal  bone  and  the  first  phalanx  of 
the  thumb  there  are  generally  two  sesamoid  bones,  and  sometimes  one  iu  the 
corresponding  joint  of  the  index  finger ; these  bones,  like  those  in  the  toot,  as 


OR  MANUAL  OF  ANATOMY. 


291 


well  as  In  other  situations,  where  they  are  occasionally  found,  as  behind  the 
condyles  of  the  femur,  in  the  heads  of  the  gastrocnemii  muscles,  do  not  pro- 
perly belong  to  the  osseous  system,  they  are  rather  accessories  to  the  tendons 
of  muscles ; they  are  found  in  the  limbs  only,  and  generally  in  the  direction 
of  flexion  ; they  are  developed  from  cartilage,  which  is  deposited  in  tendinous 
or  ligamentous  structure,  and  are  very  slow  to  ossify;  the  patella  has  some 
resemblance  to  bones  of  this  class,  it  is  however  more  perfect,  and  is  placed 
on  the  aspect  of  extension ; the  sesamoid  bones  serve  to  strengthen  the 
articulations  to  which  they  are  attached;  they  also  increase  the  power  of  the 
muscles,  by  altering  the  direction  ol  their  tendons,  and  removing  them  further 
from  the  axis  of  the  bone  which  they  are  intended  to  move. 


APPENDIX. 


DIRECTIONS  FOR  OPENING  THE  HEAD. 

The  most  common  period  of  the  dissection  for  opening  the  head,  fs,  when 
the  student  has  examined  the  attachments  of  the  occipito-frontalis,  corrugator 
super-cilii  and  temporal  muscles,  parts  most  likely  to  be  injured  in  the  opera- 
tion: having  made  a transverse  division  of  the  fibres  of  the  last  named  mus- 
cles, about  an  inch  above  the  zygoma  and  any  of  her  soft  parts  that  mav  be 
adhering:  a block  should  then  be  placed  under  the  shoulders  of  the  subject, 
which  allows  the  head  to  hang  down;  let  the  student  (having provided  him- 
self with  a heavy  hammer,  strong  in  the  claws)  take  hold  of  the  head  in  his 
left  hand,  and  with  the  right  commence  striking  steadily,  beginning  about  half 
an  inch  above  the  superciliary  rid^e,  and  continuing  it  round  on  a line  with 
the  incisions  in  the  temporal  muscle,  terminating  a little  above  the  occipital 
ridge.  No  danger  is  to  be  apprehended  of  wounding  the  brain  in  this  pro- 
ceeding, although  the  student  should  be  careful  not  to  strike  so  heavily  on  the 
temporal  or  parietal  bones  as  he  may  on  the  frontal  or  occipital,  the  former 
being  of  a much  more  brittle  texture ; when  you  have  ascertained  that  no 
part  of  the  bone  remains  unbroken,  and  have  divided  the  pericranium  with  a 
scisscrs ; your  next  step  is  to  fix  the  claws  of  the  hammer  in  the  broken  part 
of  the  frontal  bone,  and  with  a steady  pull  tear  the  skull  from  the  dura-mater. 
This  operation  requires  less  labor  and  time  than  that  done  with  a saw,  and 
ought  always  to  be  preferred,  except  in  cases  where  there  is  a wish  to  pre- 
serve the  skull,  or  in  private  houses,  where  the  feelings  of  the  relatives  are 
likely  to  be  offended  by  the  noise  made  with  a hammer.  When  the  saw  is 
used,  the  head  is  to  be  placed  on  a block,  the  cut  is  to  be  carried  round  in  the 
same  direction,  and  the  same  precautions  observed  as  described  in  using  the 
hammer:  if  much  caution  be  not  used,  the  saw  is  very  likely  to  lacerate  the 
substance  of  the  brain,  owing  to  the  inequality  of  thickness  of  the  bone.  In 
cases  however  where  the  head  is  to  be  opened  for  examination  into  the  causes 
of  death,  without  an  intention  of  pursuing  the  dissection  further,  a different 
mode  is  generally  practised  ; this  is  done  by  making  an  incision,  by  the  intro- 
duction of  the  point  of  the  knife  under  the  scalp,  commencin'!  at  one  ear, 
and  carried  over  the  vertex  to  the  other;  in  this  way  we  avoid  cutting  the 
hair,  which  in  a female  might  be  troublesome,  and  the  flaps  made  by  the 
dissection  of  the  scalp,  being  reflected  over  the  face  and  neck,  prevents  those 
parts  from  being  soiled. 

OPENING  THE  THORAX  AND  ABDOMEN. 

For  the  purpose  of  examining  the  morbid  appearance  after  death,  the  cavi 
ties  of  the  thorax  and  abdomen  are  generally  opened  at  the  same  time  ; an 


OR  MANUAL  OF  -ANATOMY. 


293 


incision  carried  down  from  the  top  of  the  sternum,  and  ending  at  the  sym- 
phvsis  pubis,  dividing  the  integuments,  muscles,  and  peritoneum,  will  bring 
the  latter  cavity  into  view ; next  let  the  skin  and  muscles  covering  the  front 
of  the  thorax  be  turned  back  which  will  expose  the  cartilages  connecting  the 
ribs  with  the  sternum;  immediately  at  their  point  of  connection  with  the 
bone,  the  cartilages  are  to  be  cut;  in  doing  this  some  caution  is  to  be  used  ; 
if  not,  the  viscera  will  sometimes  be  wounded  by  the  point  of  the  knife 
slipping  down  further  than  is  intended  ; holding  the  knife  horizontally  between 
the  thumb  and  the  middle  finger,  while  the  fore-finger,  is  placed  on  the 
back  of  the  instrument  as  a guide,  will  always  obviate  this  inconvenience. 

In  some  old  subjects,  where  the  cartilages  of  the  ribs  are  in  some  degree 
ossified,  they  will  not  yield  to  the  knife,  and  here  a saw  is  to  be  employed  ; 
all  the  cartilages,  except  those  of  the  first  rib  being  divided,  the  sternum  may 
now  be  raised  like  the  lid  of  a box,  and  a very  convenient  hinge  is  made  by 
cutting  the  articulation  of  the  first  joint  of  the  sternum  on  the  inside,  directly 
opposite  the  second  rib  ; by  following  this  rule  the  figure  of  the  thorax  will  be 
preserved,  after  the  examination  is  completed,  and  a view  sufficiently  exten- 
sive for  common  purposes,  be  obtained  of  its  contents.  The  practice  of 
making  a crucial  incision  for  the  purpose  of  examining  the  contents  of  the 
abdomen,  should  always  be  condemned,  and  should  never  supercede  the  longi- 
tudinal, as  a view  sufficiently  extensive  for  every  purpose  is  obtained  by  the 
latter;  while  the  escape  of  fluids,  and  the  unsightly  appearances  of  the  seams 
produced  by  the  former  method,  are  entirely  prevented. 

THE  MOST  COMMON  MORBID  APPEARANCES  FOUND  IN  THE  BRAIN. 

Dura  mater.  The  dura  mater  is  sometimes  found  in  a state  of  inflamma- 
tion; to  an  inexperienced  eye  this  appearance  is  difficult  of  detection,  as  in 
the  inflamed  state,  very  few  vessels  more  appear  carrying  florid  blood,  than 
in  the  natural  state  ; still,  however,  a person  well  acquainted  with  the  natural 
appearance  of  the  membrane,  would  be  as  much  struck  with  the  differences 
of  its  appearance  when  inflamed,  as  he  would  be  with  that  of  any  other  par: 
of  the  body:  in  injuries  from  external  violence,  where  inflammation  follows, 
suppuration  sometimes  occurs,  and  the  arachnoid  coat  lining  the  dura  mater 
is  found  covered  with  pus,  which  immediately  settles  the  question  of  inflam- 
mation having  existed.  Scrofulous  and  spongy  tumors  growing  from  the 
dura  mater,  producing  absorption  of  the  bone,  or  pressure  on  the  brain,  are 
occasionally  found  ; another  diseased  appearance,  although  not  very  common, 
is  a deposition  of  bony  lamina  in  some  part  of  the  dura  mater,  more  par- 
ticularly in  the  falciform  process  or  near  the  superior  longitudinal  sinus. 

Tunica  arachnoids.  The  most  common  and  almost  the  only  diseased 
structure  observed  in  the  tunica  arachnoides,  is  an  opaque  or  in  some  in- 
stances a thickened  state  of  the  membrane,  which  gives  it  a tolerable  firm 
consistence;  serous  fluid  sometimes  of  a gelatinous  nature,  is  found  between 
it  and  the  pia  mater ; and  although  these  appearances  are  said  to  depend  on 
inflammation,  still  no  vessels  holding  red  blood  are  found  ramifying  on  its 
surface. 

Pia  mater.  There  is  much  difficulty  experienced  in  distinguishing  in- 
flammation of  this  membrane  from  its  natural  state ; this  depends  on  the 


294 


THE  DUBLIN  DISSECTOR, 


great  number  of  small  vessels  which  naturally  ramify  on  it ; however,  in  the 
inflamed  state  they  become  much  more  numerous,  and  by  their  anastomosis, 
make  a beautiful  reticulated  appearance,  not  however  causing  such  a general 
redness  as  may  be  observed  in  the  inflammation  of  some  other  membranes ; 
and  when  the  inflammation  runs  high,  pus  is  formed  which  is  effused  on  the 
whole  upper  surface  of  the  brain.  Next  in  order  to  inflammation,  the  most 
common  morbid  appearance  found  in  the  pia  mater  is  the  formation  of  small 
cysts,  containing  water,  which  are  generally  called  hydatids  ; these  are  found 
more  usually  on  the  choroid  plexus,  and  in  the  velum  interpositum.  Inflam- 
mation of  the  substance  of  the  brain  is  occasionally  observed  arising  from  ex- 
ternal injury  ; the  redness,  which  is  generally  slight,  is  confined  to  one 
particular  part;  in  this  state,  when  cut  into,  the  color  appears  to  arise  from 
a great  many  small  vessels  which  are  filled  with  red  blood  ; the  inflamed  part 
is  softer  and  more  yielding  than  natural,  giving  rise  to  an  appearance  which 
has  been  lately  described  by  French  writers  and  called  “ ramollissement ;” 
when  the  inflammation  proceeds  further,  abscesses  holding  pus  are  formed, 
which,  if  of  a large  size,  break  down  the  substance  of  the  brain,  and  present  a 
very  jagged  appearance  on  their  internal  surface.  Apoplexy,  an  effusion  of 
blood  either  on  the  surface  or  in  the  substance  of  the  brain,  is  also  to  be  met 
with,  and  occasionally  into  some  of  the  ventricles,  producing  the  disease 
called  apoplexy  ; the  blood  found  in  those  situations  is  almost  always 
coagulated  ; however,  when  the  person  has  long  survived  the  apoplectic 
attack,  the  coagulated  blood  appears  to  be  taken  up  by  absorption,  and  its 
place  supplied  by  a fluid  of  an  albuminous  nature. — Hydrocephalus.  This  is 
one  of  the  most  common  affections  of  the  brain;  in  this  disease,  water  is 
found  accumulated  in  the  ventricles,  amounting  to  a few  ounces,  or  to  so 
many  pints  ; the  water,  by  raising  up  the  anterior  part  of  the  fornix  passes 
from  one  lateral  ventricle  into  the  other,  and  in  this  manner  to  the  third,  and 
so  on  to  the  fourth  ; sometimes  water  is  effused  on  the  surface  of  the  brain, 
but  this  is  rare;  the  most  common  situation  we  find  it  in  is  between  the 
arachnoid  coat  and  the  pia  mater  ; sometimes  effused  in  small  patches  between 
these  two  membranes,  and  at  others  over  a large  extent;  when  this  effusion 
takes  place,  the  vessels  of  the  pia  mater  are  found  more  distended  with  blood 
than  is  usual,  and  the  arachnoid  membrane  is  thicker  and  more  opaque  than 
in  the  natural  state;  in  most  cases  where  this  effusion  takes  place,  water  is 
also  secreted  in  the  lateral  ventricles,  and  in  the  sheath  of  the  vertebral  canal. 
Deposition  of  bony  mater  in  the  arteries  of  the  brain  may  also  be  looked  for  ; 
this  appearance  is  by  no  means  rare,  particularly  in  old  subjects:  arising 
from  this  state  of  arteries,  aneurisms  of  the  internal  carotids  are  described  by 
some  autlxors,  but  they  are  not  of  common  occurrence. 


MORBID  APPEARANCES  OF  PARTS  CONTAINED  IN  THE  THCliAX. 

Pericardium.  The  membrane  enveloping  the  heart  is  also  liable  to  inflam- 
mation; this  is  not  a very  common  disease,  although  it  occurs  sufficiently 
often  to  afford  opportunities  of  examining  its  effects  after  death  : in  the  in- 
flamed state  it  is  crowded  with  minute  vessels  carrying  florid  blood  ; it  is 
also  a little  more  pulpy  and  thicker  than  it  is  in  its  natural  state  : extrava- 
sated  coagulable  lymph  is  found  loosely  connecting  it  to  the  heart;  this  has  a 


OR  'MANUAL  OF  AMATOMY. 


295 


reticulated  appearance,  and  portions  of  it  float  in  the  serous  fluid,  which  in 
this  disease  is  found  in  the  bag  of  the  pericardium.  In  some  inflammations 
of  this  membrane  large  quantities  of  pus  are  formed,  without  any  appearance 
of  ulceration,  but  always  accompanied  with  a thickened  state,  and  a deposition 
of  coagulable  lymph  on  the  internal  surface  of  the  membrane.  The  presence 
of  a small  quantity  of  fluid  in  the  pericardium  after  death,  is  not  to  be  set 
down  as  a morbid  appearance,  or  confounded  with  the  disease  called  hydrops 
pericardii,  as  in  every  healthy  body  a few  drachms  of  fluid  are  found  in  the 
bag  of  the  pericardium,  arising  from  the  condensation  of  the  natural  vapor, 
which  exists  in  all  serous  cavities,  or  the  oozing  out  of  the  serous  parts  of  the 
blood  from  the  contraction  of  the  heart  after  death. 

To  examine  the  valves  of  the  heart,  which  are  in  many  subjects  ossified, 
the  apex  of  that  organ  may  be  cut  off,  this  will  expose  the  cavities  of  the  right 
and  left  ventricles  ; by  introducing  the  fore-flnger  into  the  right,  the  tricuspid 
and  semilunar  valves  of  the  pulmonary  artery  may  be  examined,  while  the 
same  proceeding  in  the  left  will  detect  whether  any  disease  exists  in  the 
mitral  or  semilunar  valves  of  the  aorta;  a ligature  tied  tightly  round  the 
heart  above  the  cut,  will  prevent  any  further  effusion  of  blood. — Polypi  of 
the  heart.  In  cutting  open  the  heart,  large  portions  of  coagulable  lymph  are 
found  filling  up  the  ventricles,  and  passing  for  some  way  into  the  large  arte- 
ries ; these  substances  were  formerly  considered  as  diseased  appearances,  and 
called  polypi  of  the  heart,  but  they  are  now  more  properly  classed  with  those 
changes  which  naturally  take  place  after  death,  and  are  accounted  nothing 
more  than  a simple  coagulation  of  blood.  There  are  many  other  morbid 
changes  that  take  place  in  the  structure  of  this  organ,  such  as  an  increased 
growth  of  the  muscular  fibres  of  the  ventricle,  great  wasting  of  the  parietes, 
deposition  of  fat  in  its  substance,  and  some  others,  which  a person  well 
acquainted  with  the  natural  structure  of  this  organ  will  have  little  difficulty 
in  detecting. 

Pleura.  This  membrane,  when  attacked  by  inflammation,  goes  through 
the  same  stages  as  described  when  speaking  of  inflammation  of  the  pericar- 
dium ; thickening  of  its  substance,  increased  vascularity,  terminating  in  the 
deposition  of  lymph  on  the  surface,  which  has  the  same  reticulated  appearance, 
and  in  some  cases  going  on  to  the  formation  of  purulent  fluid  and  water ; 
where  the  inflammation  has  existed  for  a considerable  time,  an  adhesion 
through  the  medium  of  coagulable  lymph  is  established  between  the  pleura 
costalis  and  pleura  pulmonalis;  when  recent  these  adhesions  are  slight  and 
easily  broken  down ; but  when  they  have  existed  for  any  considerable  length 
of  time,  they  become  so  strong  that  much  force  is  required  to  destroy  them; 
in  fact,  these  adhesions  are  the  most  common  morbid  appearances  found  in 
the  dead  body.  Parts  of  the  pleura  are  occasionally  found  converted  into 
bony  plates,  varying  in  thickness,  and  covering  a considerable  portion  of  the 
membrane;  no  inflammation  surrounds  these  bony  depositions,  and  as  no  spi- 
culoe  are  formed  on  their  surface  which  might  create  irritation,  little  inconve- 
nience attends  their  growth. 

Lungs.  Inflammation  of  the  lungs  is  almost  always  attended  with  a cor- 
responding affection  of  the  pleura;  the  inflamed  portion  has  a darker  and  more 
florid  color  than  natural,  with  an  extravasation  of  coagulable  lymph,  and  some- 
times of  blood,  into  the  substance  of  the  lungs;  the  weight  of  the  part  is 


296 


THE  DUBLIN  DISSECTOR, 


increased,  owing  to  the  extravasation  of  these  fluids,  and  therefore  it  commonly 
sinks  in  water;  this  state,  however,  is  to  be  distinguished  from  the  accumula- 
tion of  blood  in  the  more  depending  parts  after  death,  in  consequence  of  gravi- 
tation ; blood  accumulated  from  gravitation  is  always  of  a darker  color,  and 
liable  to  change  its  position;  whereas  blood  accumulated  in  an  inflamed  part 
is  more  florid  in  its  appearance,  and  remains  stationary  in  every  position  of 
the  body. — Abscess  of  the  Lung.  There  are  two  kinds  of  abscesses  found  in 
the  lungs,  one  small,  generally  arising  from  the  suppuration  of  one  or  more 
tubercles,  the  other,  which  is  the  common  scrofulous  abscess,  eimairin'r  nearly 
the  Whole  of  the  substance  of  the  lung,  they  discharge  themselves  by  ulcerated 
openings,  generally  into  the  trachea,  or  opening  into  the  cavity  of  the  thorax, 
they  pour  out  their  contents  ; and  this  is  one  of  the  causes  of  empyema. 

Tubercles  of  the  Lungs.  There  is  no  morbid  appearance  more  common  in 
the  lungs  than  that  of  tubercles;  they  consist  of  round  firm  bodies,  formed  in 
the  cbllular  substance,  connecting  the  air  cells  of  the  lungs  together;  they 
are  at  first  very  small,  not  being  larger  than  the  heads  of  pins,  though  the 
ordinary  size  is  that  of  a pea;  when  many  of  the  smaller  ones  are  clustered 
together,  theyr  probably  grow  into  one  another,  and  form  large  tubercles  ; they 
have  no  evident  capsules,  and  possess  little  or  no  vascularity  ; when  cut  into, 
they  present  a white  firm  texture,  and  they  often  in  part  contain  a thick  curdy 
pus,  and  not  unfrequently  osseous  matter;  in  cutting  into  the  lungs,  a num- 
ber of  abscesses  are  found,  from  many  of  the  tubercles  having  advanced  into 
a state  of  suppuration,  it  has  been  remarked,  that  tubercles  have  been  found 
in  the  upper  portion  of  the  right  lung,  where  there  has  been  an  impossibility 
of  detecting  them  in  any  other  part. 

MORBID  APPEARANCES  IN  THE  ABDOMEN. 

Peritoneum.  This  membrane  lining  the  internal  surface  of  the  abdomen  and 
investing;  the  different  viscera,  although  not  so  liable  to  inflammation  as  the 
pleura,  yet  it  is  not  uncommonly  inflamed  ; when  inflammation  is  present,  it 
appears  more  pulpy,  than  in  the  natural  state,  it  is  not  so  transparent,  and  is 
crowded  with  anumber  of  small  vessels,  holding  florid  blood  ; where  this  mem- 
brane covers  the  intestinal  canal,  the  inflammation  appears  to  penetrate  nearly 
as  far  as  the  mucous  coat ; sometimes  the  inflammation  is  confined  to  particu- 
lar parts  and  at  others  it  spreads  over  the  whole  membrane ; when  the  inflam- 
mation is  great  the  intestines  become  thick  and  massy,  arising  from  the  accu- 
mulation of  fluids  in  the  small  vessels  and  extravasation  of  coagulable  lymph 
between  their  tunics  ; this  appearance  may  be  observed  in  the  omentum,  where 
fluids  of  this  nature  are  thrown  out  between  its  different  lamina ; layers  of 
coagulable  lymph  gluing  different  portions  of  the  abdominal  viscera  together, 
a brownish  fluid,  which  is  serum  and  some  pus,  in  which  shreds  ot  coagulable 
lymph  float,  are  common  appearances;  if  the  patient  survive  the  attack  of  in- 
flammation, this  coagulable  lymph  becomes  organized  and  the  adhesions  which 
it  forms  become  permanent,  and  are  to  be  met  with  in  many  bodiesafter  death: 
an  inflammation  resembling  the  above  occurs  frequently  in  women  who  have 
been  recently  delivered,  it  is  called  puerperal  peritonitis,  the  uterus  is  found 
dilated,  and  it  is  so  fatal  in  its  progress,  that  it  seldom  advances  to  the  forma- 
tion of  permanent  adhesions. 


OR  MANUAL  OF  ANATOMY. 


297 


Peritoneal  Abscess  occurs  in  the  cellular  substance  connecting  the  perito- 
neum to  the  viscera,  the  most  common  situation  we  find  it  in  is  between  the 
convex  surface  of  the  liver  and  diaphragm  ; when  it  opens,  it  is  bj  ulcerated 
communications  with  the  stomach  or  transverse  arch  of  the  colon. 

Stomach.  Inflammation  of  the  stomach  is  rare,  except  in  cases  of  poison  ; 
when  it  is  inflamed,  the  mucous  membrane  appears  pulpy  and  very  vascular, 
occasionally  with  some  extravasation  of  blood  between  the  middle  and  mucous 
coats:  ulcers  of  the  stomach  are  sometimes  to  be  met  with,  they  are  unlike 
ulcerations  in  ether  parts  ; they  are  generally  circular  in  their  shape,  with  the 
edges  smooth,  defined  and  looking  as  if  they  were  healed;  the  stomach  is 
thickened  in  their  neighborhood,  although  this  is  nbt  always  the  case;  an  ap- 
pearance that  may  be  confounded  with  ulcer  of  the  stomach  is,  where  the 
gastric  juice  acts  upon  this  organ  after  death,  and  produces  digestion  of  its 
several  coats  ; this  latter  process  causes  a lacerated  ragged  appearance  of  the 
edges,  while  an  ulcer  of  the  stomach  looks  as  if  a circular  piece  were  removed 
by  the  cut  of  a knife. 

Pylorus.  The  pyloric  extremity  of  the  stomach  is  often  found  much 
thickened  ; this  induration  is  generally  of  a cancerous  nature,  it  is  some- 
times so  great,  as  to  prevent  the  passage  of  the  food  into  the  duodenum  ; 
when  it  extends  into  the  stomach  this  organ  becomes  indurated,  ulceration 
takes  place,  and  cancer  of  the  stomach  is  then  said  to  exist. 

Intestines.  The  intestinal  canal  is  very  subject  to  inflammation,  increased 
vascularity  of  the  mucous  coat,  with  thickening  of  all  the  tunics,  denote  this 
inflammation;  except  in  violent  states  of  inflammation,  the  peritoneal  coat 
is  not  engaged.  The  color  of  the  intestine  is  sometimes  very  dark,  from  a 
large  quantity  of  black  extravasated  blood  retained  between  its  tunics ; this 
appearance  is  often  improperly  mistaken  for  mortification  ; when  the  inflam- 
mation is  confined  to  the  mucous  coat,  it  often  terminates  in  ulceration  ; the 
ulcers  which  are  on  the  mucous  membrane  have  some  difference  in  their  ap- 
pearance, sometimes  having  a thickened  raised  edge,  and  at  others,  not  ele- 
vated at  all  above  the  surface ; according  to  scflne,  ulceration  more  frequently 
takes  place  in  the  situation  of  the  glandulae  agminatse;  ulceration  however 
does  not  appear  to  be  so  common  in  the  small  as  in  the  great  intestines ; in 
dysenteric  affections  of  the  great  intestines,  a great  portion  of  the  inner 
membrane  is  found  hanging  in  shreds,  occasioned  by  the  great  ravages  of  the 
ulceration;  while  in  some  places,  large  patches  of  the  mucous  membrane 
have  been  totally  stripped  off,  leaving  the  submucous  coat  quite  bare,  and 
appearing  as  if  it  had  been  dissected;  where  this  unfortunately  happens,  the 
mucous  membrane  is  never  afterwards  repaired. — Liver.  The  peritoneal 
coat  covering  the  liver,  is  not  uncommonly  found  in  a state  of  inflammation 
it  is  either  affected  by  itself,  or  is  included  in  general  peritonitis  ; where  the 
former  happens,  the  anterior  or  convex  surfaces  are  generally  the  parts  in- 
flamed, the  same  appearances  exist,  as  described  when  speaking  of  peritonitis, 
viz:  great  crowding  of  small  vessels  containing  florid  blood,  increased  thick- 
ness and  pulpiness  of  the  membrane  and  an  effusion  of  coagulable  lymph  on 
the  surface,  which  when  organized  forms  permanent  adhesions  to  the  neigh- 
boring viscera,  and  are  found  to  exist  more  or  less  in  every  adult  dead  body. 
When  the  substance  of  the  liver  is  inflamed  (which  is  a rare  occurrence  in 
these  countries,)  it  becomes  enlarged  in  size  and  of  a purple  color,  and 
38 


298 


THE  DUBLIN  DISSECTOR, 


harder  to  the  touch  than  in  its  healthy  state ; if  the  inflammation  continue  for 
any  length  of  time,  abscesses  are  formed,  which  in  some  cases  contain  many 
pints  of  pus  ; in  persons  laboring  under  an  abscess  of  this  kind,  contracted 
in  a warm  climate,  the  liver  will  be  found  almost  entirely  converted  into  a 
bag  holding  nothing  but  pus.  From  the  adhesions  of  the  viscera  from  the 
previous  inflammation,  these  abscesses  generally  discharge  themselves  by 
ulcerated  openings  into  the  stomach,  transverse  arch  of  the  colon,  or  some 
coil  of  the  small  intestine. 

Tubercles  of  the  liver.  To  describe  the  different  kinds  of  tubercles  men- 
tioned by  authors,  is  not  our  intention,  as  it  would  only  tend  to  embarrass  the 
student,  without  being  of  any  essential  service  to  him,  more  particularly  as 
writers  themselves  do  not  quite  agree  in  their  description  of  them.  One  of 
the  most  common  diseases  of  the  liver  (if  we  except  adhesions)  is  the  tuber- 
culated  state  of  the  organ ; this  appearance  is  never  met  with  in  young  persons, 
but  seems  to  be  peculiar  to  the  adult  and  aged ; the  whole  of  its  substance  is 
generally  engaged,  and  when  this  is  the  case,  the  liver  becomes  much  harder, 
irregular  on  its  surface,  and  smaller  in  size  than  natural ; dropsy  of  the  ab- 
domen generally  accompanies  this  state  of  the  organ. — Hydatids.  There  is 
no  gland,  except  the  kidney,  in  which  hyatids  are  so  frequently  found  as  in 
the  liver;  they  are  contained  in  cysts  of  a cartilaginous  nature,  in  the  sub- 
stance of  the  organ;  sometimes  the  cyst  holds  but  one  of  these  animalcules, 
and  in  others  it  contains  many  varying  in  size  from  that  of  a pin’s  head  to  a 
hen’s  egg;  rarely  they  are  found  attached  to  the  inside  of  the  cyst,  but  gene- 
rally floating  in  the  serous  fluid  which  it  contains. — Cysts.  Cysts  of  a car- 
tilaginous structure,  holding  earthy  matter,  are  also  found  lodged  in  the 
substance  of  the  liver. — Gall  bladder.  When  the  substance  of  the  liver  is 
inflamed,  the  gall  bladder  takes  on  the  inflammatory  process,  but  seldom 
proceeds  into  ulceration ; the  most  common  morbid  appearance,  discovered 
in  this  viscus,  is  the  formation  of  gall  stones  : when  there  is  but  one  in  the 
gall  bladder,  it  is  generally  a large  oval  one,  closely  filling  up  the  cavity  of 
the  bag,  and  preventing  it  from  receiving  bile  ; but  oftener  it  contains  many, 
even  amounting  to  some  hundreds,  and  from  rubbing  on  each  other  in  a small 
space,  they  acquire  many  sides  and  angles  ; calculous  matter  as  fine  as  powder, 
is  also  to  be  met  with  in  the  gall  bag. — Spleen.  The  membrane  covering  the 
spleen  is  inflamed  in  general  peritonitis  ; the  appearance  is  the  same  as  that 
which  is  so  often  described  in  speaking  of  the  inflammations  of  other  viscera ; 
the  substance  of  the  spleen  is  rarely  inflamed,  and  abscess  is  not  common  ; 
the  softness  described  by  some  authors  can  scarcely  be  considered  a deviation 
from  natural  structure.  The  coats  of  the  spleen  are  sometimes  converted 
into  cartilaginous  or  bony  matter,  and  this  disease  may,  in  a great  measure, 
be  considered  as  peculiar  to  the  spleen. — Pancreas.  The  pancreas  is  rarely 
found  in  a diseased  state ; calculi  have  been  found  in  its  ducts,  it  has  also 
been  seen  harder  in  its  structure  than  natural,  approaching  the  nature  ot 
cancer,  and  one  or  two  cases  of  abscess  in  its  substance  have  been  described. 
Kidneys.  From  the  loose  connection  which  the  peritoneum  has  with  the 
capsule  of  the  kidney,  this  membrane  is  not  so  liable  to  be  inflamed  in  peri- 
tonitis, as  the  investing  membranes  of  other  organs  ; the  substance  however, 
is  often  inflamed,  and  is  very  much  disposed  to  form  abscesses.  Abscesses 
of  the  kidney  are  of  two  kinds;  one,  which  is  the  scrofulous,  being  the  most 


OK  MANUAL  OF  ANATOMY. 


£99 


common,  containing  white  curdy  pus,  the  other  generally  arises  from  the 
irritation  produced  by  calculi,  and  bears  all  the*appearances  of  phlegmonous 
abscess  : in  the  first  instance  they  destroy  the  mammillary  portion,  and  if  they 
proceed,  the  whole  structure  of  the  kidney  is  destroyed,  leaving  nothing  but 
a capsule,  lined  with  a pulpy  substance,  which  the  walls  of  the  abscess 
secreted. — Hydatids.  Hydatids  are  often  found  between  the  substance  of 
the  kidney  and  its  capsule  ; they  are  not  enclosed  in  firm  cysts,  nor  are  their 
coats  so  thick  as  those  found  in  the  liver ; another  distinction  remarked  is,  that 
in  the  kidney  they  are  generally  all  of  the  same  size,  while  in  the  liver  they 
vary  very  much,  as  has  been  already  mentioned. — Calculi.  The  formation 
of  calculi  is  not  peculiar  to  the  kidneys,  but  it  is  a more  frequent  disease  in 
them  than  in  any  other  part  of  the  botfly;  sometimes  they  are  small,  and  are 
found  in  the  tubular  portion,  but  more  commonly  one  calculus  of  considerable 
size  is  met  with,  lodged  in  the  substance  of  the  kidney  or  filling  up  the  pelvis 
of  the  ureter  ; when  it  is  so  large  as  not  to  be  capable  of  passing  through  the 
ureter,  additional  calculous  matter  is  laid  on,  and  in  its  growth  it  is  neces- 
sarily accommodated  by  the  parts  which  contain  it.  and  becomes  branched  in 
its  shape  from  extending  into  the  infundibula.  When  a calculus  in  the  pelvis 
of  the  kidney  has  increased  to  a large  size,  it  almost  prevents  the  passage  of 
the  urine  into  the  ureter,  the  urine  becomes  accumulated  above  the  stone,  and 
enlarges  the  pelvis  and  infundibula.  If  there  be  obstruction  to  the  passage 
of  urine,  from  a stone  being  lodged  in  the  extremity  of  the  ureter  near  the 
bladder,  not  only  is  the  pelvis  of  the  kidney  greatly  enlarged,  but  the  ureter 
itself  partakes  of  the  dilitation  : as  this  process  advances,  the  substance  of 
the  kidney  becomes  more  and  more  compressed,  is  gradually  absorbed,  and 
nothing  is  left  but  a capsule,  containing  numerous  cells,  communicating  with 
one  another. 

Bladder.  The  mucous  membrane  of  the  bladder  is  occasionally  found 
inflamed,  the  inflammation  may  be  general  or  confined  to  one  particular  part; 
the  portion  which  is  most  frequently  inflamed  is  that  near  the  neck,  and  com- 
monly arises  from  the  presence  of  a rough  stone : from  the  naturally  pale 
appearance  of  the  mucous  membrane  in  the  dead  body,  any  crowding  of  ves- 
sels containing  arterial  blood  which  takes  place  in  inflammation  makes  this 
state  of  parts  easy  of  detection ; if  the  inflammation  be  violent,  the  muscular 
coat  may  become  engaged,  and  abscesses  and  ulcers  are  not  unfrequently  the 
consequence;  they  sometimes  proceed  so  far  as  to  destroy  a portion  of  the 
bladder,  and  form  communications  between  it  and  the  neighboring  viscera ; 
with  the  rectum  in  the  male,  and  vagina  in  the  female ; they  have  also  been 
known  to  open  into  the  cavity  of  the  abdomen,  producing  peritonitis  and  death 
from  extravasation  of  urine  : abscesses  about  the  neck  of  the  bladder  are 
generally  found  as  a consequence  of  the  operation  of  lithotomy  being  badly 
performed. — Calculi.  Calculi  are  not  uncommonly  formed  in  the  bladder ; their 
formation  is  confined  to  no  particular  period  of  life;  they  are  formed  in  very 
young  children  and  persons  of  middle  and  advanced  age;  they  are  very 
seldom  met  with  in  females ; this  is  owing  to  the  size  of  the  urethra  in  that  sex, 
which  allows  them  to  be  discharged  before  they  become  large,  and  also  from  a 
tendency  to  their  formation  not  being  so  strong  in  females.  The  stones  which 
are  found  in  the  bladder  are  either  originally  formed  in  the  kidneys,  and  pass 
through  the  ureters  into  the  bladder,  or  they  are  at  first  formed  in  the  bladder 


300 


THE  DUBLIN  DISSECTOR, 


itself.  Calculi  lie  either  loosely  in  the  cavity  of  the  bladder,  or  are  confined 
to  some  fixed  situation  from  particular  circumstances ; when  they  are  of  a 
small  size,  they  are  sometimes  lodged  in  pouches,  formed  by  the  protrusion 
of  the  mucous  coat  of  the  bladder,  between  the  fasciculi  of  its  muscular  fibres. 
Urinary  calculi  have  sometimes  a smooth,  uniform  surface,  but  more  fre- 
quently the  surface  is  granulated  and  rough. — Prostate  Gland.  This 
gland  is  scarcely  ever  found  diseased  except  in  old  men;  it  is  rarely 
inflamed,  an  abscess  however  has  been  met  with  (unaccompanied  bv 
any  thickening)  in  its  substance,  arising  from  common  inflammation. 
Scirrlvus.  The  most  common  disease  of  the  prostate  gland  is  scirrhus;  the 
gland  in  its  natural  state  is  known  to  be  about  the  size  of  a chestnut,  but 
when  it  is  affected  with  scirrhus,  it  is  often  enlarged  to  the  size  of  the  fist. 
The  common  appearances  observed  in  scirrhus  in  other  parts  of  the  body,  can 
be  plainly  seen  in  this  gland  ; when  cut  into,  it  appears  to  consist  of  a very 
solid,  whitish,  or  brown  substance,  with  membranous  septa,  running  through 
it  in  various  directions.  According  to  the  degree  of  enlargement  that  takes 
place,  the  urine  is  passed  through  the  bladder  with  greater  or  less  difficulty, 
as  well  as  an  instrument  for  drawing  it  off.  Calculi  have  been.found  lodged 
in  the  ducts  of  the  prostate  gland  ; they  are  usually  small  granules  of  a dark 
color,  and  give  it  a mottled  appearance  when  cut  into. 

Uterus.  When  the  uterus  becomes  inflamed,  it  takes  place  almost  under 
the  same  circumstances,  viz.  very  soon  after  parturition.  When  it  is  inflamed 
the  peritonaeum  in  the  neighborhood  is  most  commonly  affected,  and  fre- 
quently over  its  whole  extent.  The  uterus,  when  inflamed,  exhibits  the  same 
appearances  as  the  inflammation  of  the  substance  of  other  parts ; the  inflam- 
mation is  found  to  creep  along  the  appendages  of  the  uterus,  especially  the 
Fallopian  tubes  and  ovaries.  It  often  advances  to  suppuration,  and  the  pus 
is  generally  found  in  the  large  veins  of  the  womb.  When  the  peritonseum  is 
affected  by  the  inflammation,  it  has  been  remarked,  that  the  extravasated 
fluid  and  coagulable  lymph  are  found  in  a greater  proportion  to  the  de- 
gree of  inflammation,  than  in  common  peritonitis. — Polypus.  Polypi  are 
very  frequently  found  in  the  uterus;  they  may  grow  at  any  period  of  life, 
but  they  are  rarely  met  with  in  the  young.  By  a polypus  is  meant 
a diseased  mass,  which  adheres  to  the  cavity  of  the  uterus,  by  a sort  of 
neck  or  narrower  portion.  Polypus  is  of  two  different  kinds ; the  most  com- 
mon kind  is  hard,  and  consists  of  a substance  divided  by  thick  membranous 
septa  ; this  sort  of  polypus  varies  very  much  in  its  size,  some  not  being  larger 
than  a walnut,  and  others  being  larger  than  a child’s  head.  Another  sort  of 
polypus  forms  in  the  uterus,  which  consists  of  an  irregular  bloody  substance, 
with  tattered  processes  hanging  from  it ; when  cut  into  it  appears  to  be  a 
spongy  mass,  holding  large  cells.  The  most  common  part  to  which  polypi 
adhere,  is  the  fundus  uteri,  and  sometimes  they  are  found  attached  to 
the  os  tincse. — Ovaria.  The  membrane  covering  or  the  substance  of  the 
ovaria,  are  very  rarely  found  inflamed,  except  when  they  are  included 
in  general  peritonitis  ; when  the  inflammation  proceeds  from  the  uterus, 
it  sometimes  goes  on  to  the  formation  of  pus  in  the  ovary. — Dropsy.  The 
most  common  disease  in  the  ovary  is  dropsy,  the  whole  substance  of  the 
ovarium  is  sometimes  converted  into  a capsule  containing  fluid.  When 
the  ovaria  have  become  dropsical,  their  natural  structure  has  disappeared, 


OR  MANUAL  OF  ANATOMY. 


301 


and  they  are  found  converted  into  cells,  communicating  with  one  another 
by  considerable  openings,  and  very  much  enlarged : the  ovaria  are  some- 
times converted  into  a series  of  cysts,  which  have  no  communication  with 
each  other;  these  cysts  have  been  confounded  with  hydatids,  to  which  they 
bear  some  resemblance ; they  are,  however,  very  different ; they  have  much 
firmer  and  less  pulpy  coats  than  hydatids,  they  contain  a different  kind  of 
fluid,  and  they  are  differently  connected  among  themselves.  Hydatids  either 
lie  unconnected,  or  one  large  one  encloses  a number  of  small  ones;  while 
ovarian  cysts  adhere  to  each  other  by  broad  surfaces,  and  do  not  enclose  each 
other.  The  ovaria  are  sometimes  found  converted  into  cysts,  holding  large 
masses  of  fat,  hair,  and  some  teeth ; these  substances  appear  to  be  generated 
by  the  internal  membrane  of  the  cyst;  the  hairs  are  most  of  them  loose  in  the 
fatty  substance,  but  many  of  them  adhere  to  the  inside  of  the  capsule;  the 
teeth,  which  are  not  always  perfect,  are  sometimes  attached  to  the  cyst,  and 
at  others,  to  an  irregular  mass  of  bone. 

LAENNEc’s  DIVISION  OF  THE  REGIONS  OF  THE  THORAX. 

The  chest  of  a healthy  person,  when  slightly  struck,  ought  to  yield  over 
its  whole  extent  a clear  and  distinct  sound.  The  character  of  the  sound  de- 
rived from  percussion,  is  different  in  the  different  parts  of  the  chest;  on  which 
account  it  has  been  divided  by  Laennec  into  fifteen  regions,  twelve  of  which 
are  double. 

1.  Subclavian  region.  This  includes  merely  that  portion  of  the  chest 
covered  by  the  clavicle.  When  struck  about  the  middle  or  external  extre- 
mity, this  bone  yields  a clear  sound,  but  its  humeral  extremity  gives  rather  a 
dull  sound  : a knowledge  of  the  morbid  or  natural  sounds  of  the  chest  in  this 
region,  is  of  great  importance;  for  from  it  are  usually  derived  the  first  signs 
of  the  development  of  tubercles  in  the  lungs,  which  are  found  in  the  upper 
part  of  the  right  lung,  even  where  they  exist  in  no  other  part  of  the  chest. 

2.  Anterior  superior  region.  This  is  bounded  by  the  clavicle  and  by  the 
fourth  rib  (inclusive)  below.  The  sound,  though  clear,  is  somewhat  less  so 
than  over  the  sternal  end  of  the  clavicle. 

3.  Mammary  region.  This  begins  below  the  fourth  rib,  and  terminates 
with  the  eighth.  In  the  female,  the  mammary  gland,  in  the  mate,  the  inferior 
edge  of  the  pectoralis  major  prevents  this  region  from  yielding  as  good  a sound 
as  the  anterior  superior  region. 

4.  Submammary  region.  This  extends  from  the  eighth  to  the  cartilaginous 
border  of  the  false  ribs.  On  the  right  side  the  sound  is  often  dull,  caused  by 
the  size  of  the  liver;  while  on  the  left,  the  sound  is  frequently  more  clear 
than  natural,  which  is  attributed  to  the  presence  of  the  stomach  distended 
with  gas. 

Sternal  regions,  5 superior;  6 middle;  and  7 inferior.  The  sound  is 
as  clear  over  the  whole  extent  of  the  sternum,  as  on  the  sternal  end  of  the 
clavicle.  However,  the  inferior  region  sometimes  yields  a duller  sound,  in 
consequence  of  the  accumulation  of  fat  about  the  heart. 

8.  Axillary  region.  This  extends  from  the  axilla  to  the  fourth  rib  inclu- 
sive: the  sound  here  is  naturally  clear. 

9.  Lateral  region.  This  is  bounded  by  the  fourth  rib  above,  and  terminates 


sm 


THE  DUBLIN  DISSECTOR, 


with  the  eighth.  The  sound  is  always  good  on  the  left  side;  on  the  right  it  is 
altered  frequently  by  the  liver  rising  higher  than  usual,  and  compressing  the 
right  lung. 

10.  Inferior  lateral  region.  This  is  bounded  above  by  the  eighth  rib,  and 
terminates  at  the  border  of  the  false  ribs.  This  region  also,  on  account  of  the 
liver,  yields  often  a completely  dull  sound  on  the  right  side,  while  on  the  con- 
trary the  left,  for  reasons  before  mentioned,  gives  a clearer  sound  than  natural, 
even  where  there  be  effusion  of  fluid  into  the  pleura,  or  where  the  inferior 
portion  of  the  left  lung  be  obstructed. 

11.  Acromial  region.  This  is  comprehended  between  the  clavicle,  the 
upper  edge  of  the  trapezius,  the  head  of  the  humerus,  and  the  lower  part  of 
the  neck.  The  soft  parts  interposed  in  this  place  prevent  all  sound  from 
percussion. 

12.  Upper  scapular  region.  This  corresponds  to  the  supra-spinous  fossa 
of  the  scapula,  and  yields  hardly  any  sound  on  account  of  the  muscle  which 
fills  it.  The  spine  of  the  scapula,  which  forms  the  inferior  boundary  of  this 
region,  sometimes  yields  a faint  sound  when  the  arms  are  strongly  compressed 
across. 

13.  Lower  scapular  region.  This  corresponds  to  the  infra-spinous  portion 
of  the  scapula.  It  yields  no  sound  on  percussion  because  this  portion  of  the 
clavicle  is  covered  by  the  infra-spinous  muscle. 

14.  Inter-scapular  region.  This  includes  the  space  between  the  dorsal 
edge  of  the  scapula  and  the  spine,  when  the  arms  are  crossed  on  the  breast. 
The  muscles  of  this  region  necessarily  render  every  sound  dull;  some- 
times, however,  in  thin  persons,  it  gives  a low  but  distinct  sound,  if  the  head  be 
bent  and  the  arms  crossed  in  order  to  make  tense  the  trapezius  and  rhomboidei 
muscles.  The  spine  in  this  region  gives  a good  sound  ; as  likewise  that  por- 
tion of  the  chest  included  between  the  superior  dorsal  angle  of  the  scapula 
and  the  first  dorsal  vertebra. 

15.  Inferior  dorsal  region.  This  begins  at  the  level  of  the  inferior  angle 
of  the  scapula,  terminating  at  the  twelfth  dorsal  vertebra.  Percussion  of  this 
region  should  be  made  in  a transverse  direction,  on  the  angle  of  the  ribs ; in 
the  upper  part,  the  sound  is  sufficiently  good  ; in  the  lower  it  is  slight,  or  often 
does  not  exist,  especially  on  the  right  side,  from  the  presence  of  the  liver ; on 
the  left  side  it  frequently  gives  an  unnaturally  clear  sound,  on  account  of  the 
distended  state  of  the  stomach. 

A CONCISE  VIEW  OF  THE  LIGAMENTS  AND  MUSCLES  CONCERNED  IN  SIMPLE 

DISLOCATIONS. 

A simple  dislocation  is  the  separation  of  the  articulatory  surfaces  of  a joint 
accompanied  by  rupture  of  ligaments,  but  without  fracture ; by  which  the 
motions  of  the  joint  are  impeded  or  suspended.  The  action  of  muscles  with 
respect  to  luxations  is  of  two  kinds ; one,  in  producing  dislocation ; the  other, 
in  resisting  reduction.  The  first  is  a simple  contraction  of  the  muscle  by 
which  dislocation  is  produced  when  the  articulating  surfaces  are  placed  in  a 
position  mechanically  favoring  this  accident.  The  second  is  that  slow  con- 
traction of  the  muscle,  (called  tonic,)  which  invariably  takes  place  when  the 
points  of  its  attachment  are  approximated.  Examples  of  both  kinds  are  best 


OR  MANUAL  OF  ANATOMY. 


503 

illustrated  by  dislocations  of  the  shoulder  joint.  When  the  arm  is  raised 
from  the  body  violent  action  of  the  pectoralis  major,  latissimus  dorsi  and  teres 
major  muscles,  may  pull  the  head  of  the  bone  down  into  the  axilla;  and  when 
this  displacement  has  occured,  the  contraction  of  the  pectoral  and  other 
muscles  still  going  on,  though  more  slowly,  will  bring  the  head  of  the  bone 
forwards  towards  the  sternum  and  clavicle ; and  present  a strong  obstacle  to 
reduction. 

OF  DISLOCATION  OF  THE  HEAD  FROM  THE  FIRST  CERVICAL  VERTEBRA. 

A dislocation  of  the  head  from  the  first  cervical  vertebra  has  only  been 
found  in  consequence  of  disease.  The  displacement  may  occur,  either  for- 
wards, backwards,  or  to  either  side,  compressing  powerfully  the  spinal  mar- 
row. These  kind  of  dislocations  taking  place  from  internal  causes  are  not  in 
any  degree  affected  by  the  neighboring  muscles ; but  the  anterior  and  poste- 
rior ligaments,  with  the  odontoid,  must  be  injured  in  any  displacement  for- 
wards or  backwards.  It  is  to  be  remarked  that  dislocation  of  the  dentata,  or 
of  one  or  more  of  the  cervical  vertebrae,  always  accompany  this  displacement 
of  the  atlas 


OF  DISLOCATION  OF  THE  ATLAS  FROM  THE  AXIS. 

The  first  cervicial  vertebra  may  be  dislocated  from  the  second ; first,  di- 
rectly backwards,  with  the  laceration  of  the  transverse,  and  odontoid  ligaments ; 
and  of  the  apparatus  ligamentosus  colli.  The  inter-transverse  muscle  is  also 
torn. 

2nd,  By  a violent  rotation  of  the  head,  the  lateral  portions  of  the  transverse 
ligament,  and  the  odontoid  being  ruptured,  the  dentata  may  slip  back  under 
the  transverse  ligament,  and  thus  be  dislocated. 

3rd,  By  a fracture  of  the  processes  dentatus.  This  may  take  place  when 
violence  is  applied  in  such  a direction  that  the  ligaments  attached  to  the  pro- 
cessus dentatus  are  powerfully  extended,  by  which  this  process  is  broken  off. 
Simple  dislocation  of  the  atlas  from  the  axis  has  hithereto  been  considered  the 
only  one  which  can  take  place  in  the  cervical  region.  Between  the  occipital  bone 
and  first  cervicial  vertebra  it  cannot  happen  from  external  force ; because,  though 
there  are  no  strong  connecting  ligaments,  the  articulatory  surfaces  are  too  close- 
ly joined,  and  the  movements  between  them  too  slight  and  limited.  Besides,  the 
rotary  motion  of  the  head,  in  which  alone  this  accident  could  occur,  is  strictly 
confined  to  the  atlas  and  axis.  Obstacles  still  more  powerful  oppose  a dislo- 
cation of  the  other  cervical  vertebras.  The  oblique  direction  of  the  articula- 
tory surfaces,  by  which  rotation  is  prevented;  the  peculiar  mode  in  which 
the  bodies  of  these  vertebras  are  articulated ; not  with  a smooth  surface,  as  in 
the  dorsal,  but  with  a depression  on  the  superior  surface,  from  which  two  hook- 
like processes  ascend  and  embrace  the  body  of  the  vertebra  above  it : the 
inter-spinous  and  inter-transverse  muscles,  which  exist  in  this  part  of  the  spine 
only ; the  strength  of  the  inter -vertebral  substance,  which  being  of  less  depth 
here  will  not  readily  yield  : and  above  all,  the  limitation  to  motion,  partly  pro- 
duced by  the  mechanical  forms  of  the  bones,  partly  by  the  mode  of  action 
of  the  muscles  : these  circumstances  concur  to  render  a dislocation  of  one 


304 


THE  DUBLIN  DISSECTOR, 


cervical  vertebra  from  another,  without  fracture,  extremely  difficult.  In  fact  it 
has  hitherto  been  considered,  by  the  greater  number  of  writers,  as  an  accident, 
which  could  not  occur  ; but  an  example  of  simple  dislocation  forwards  of  the 
fourth  from  the  fifth  cervical  vertebra  was  lately  seen  in  St.  Bartholomew’s 
Hospital ; and  a similar  accident  occured  still  more  lately  in  this  country 

OF  DISLOCATION  OF  THE  LOWER  JAW. 

The  structure  of  the  articulation  of  the  lower  jaw  renders  it  impossible  for 
any  other  than  the  forward  dislocation  to  take  place.  This  most  readily  hap- 
pens when  the  mouth  is  opened  widely,  or  when  any  violence  is  used  which 
tends  to  depress  the  lower  jaw.  In  such  case,  the  condyle  being  brought  for- 
wards to  the  anterior  edge  of  the  articular  eminence,  if  the  pterygoideus 
externus  and  anterior  portion  of  the  masseter  act  strongly,  the  condyle  slips 
forwards  under  the  zygoma,  and  the  dislocation  is  produced.  Usually  the 
internal  lateral  ligament  alone  is  ruptured,  unless  the  displacement  has  been 
occasioned  by  some  sudden  violence.  The  muscles  which  depress  the  lower  jaw, 
and  thus  assist  in  producing  luxation,  are  the  platisma  myoides,  the  digastric  ; 
the  mylo-hyoideus;  the  genio-hyoideus,  and  the  genoi-hyo-glossus.  Both  con- 
dyles may  be  dislocated  at  the  same  time  ; or  one  separately.  The  first  is 
called  complete  dislocation;  the  latter,  a partial  dislocation;  but  this  nomen- 
clature is  to  be  condemned  as  leading  to  confusion  of. the  terms.  When  dis- 
location of  both  condyles  has  taken  place  the  mouth  remains  permanently 
open,  in  consequence  of  the  coronoid  process  resting  on  the  angle  between 
the  malar  and  maxillary  bones.  The  line  of  the  lower  arch  of  the  teeth,  in- 
stead of  falling  behind  the  upper,  as  in  the  natural  position,  falls  before  them: 
there  is  a depression  in  front  of  the  ear,  where  the  condyle  of  the  lower 
jaw  should  be  felt,  and  the  muscles  of  the  side  of  the  face  appear  flat  and 
diminished.  When  displacement  of  one  condyle  only  occurs,  the  arches  of 
the  teeth  of  the  upper  and  lower  jaws  do  not  correspond  ; and  the  depression 
in  front  of  the  ear  is  only  felt  on  the  dislocated  side  The  muscles  concerned 
in  a dislocation  of  the  lowrer  jaw  are  the  depressing  muscles  of  the  jaw  ; the 
two  pterygoid  muscles,  but  chiefly  the  external ; and  the  anterior  portion  of 
the  masseter. 

OF  DISLOCATION  OF  THE  CLAVICLE. 

At  its  sternal  end  the  clavicle  may  be  dislocated  upwards,  forwards  or  back- 
wards. Displacement  upwards  or  backwards  are  too  rare  to  merit  any  notice. 
In  dislocation  forwards  the  anterior,  posterior,  and  inter-clavicular  ligaments 
are  ruptured ; and  occasionally  the  tendinous  expansion  of  the  sterno-cleido- 
mastoid  on  the  clavicle  and  sternum.  The  costo-clavicular  ligament  must 
also  be  ruptured;  and  this  is  the  one  which  chiefly  resists  displacement  when 
the  shoulder  is  elevated.  At  its  scapular  extremity,  the  clavicle  may  be  dis- 
placed either  above  or  below  the  acromion ; the  latter  case  is  extremely  rare. 
When  the  clavicle  passes  above  the  acromion,  the  shoulder  inclines  in,  being 
unsupported  by  this  bone,  and  its  extremity  projects  under  the  skin  ot  the 
shoulder.  The  superior,  inferior,  and  coraco-clavicular  ligaments  are  sometimes 
ruptured.  The  clavicular,  portion  of  the  trapezius  is  the  only  mu'scle  which 
by  elevating  the  clavicle,  can  assist  in  this  displacement. 


OR  MANUAL  OF  ANATOMY, 


305 


OF  DISLOCATION  OF  THE  HUMERUS. 

The  shoulder  joint,  from  the  great  extent  of  its  motions  and  forms  of 
its  articulating  surfaces,  is  more  liable  to  dislocation  than  any  other  in  the 
body. 

Primary  dislocations  of  the  humerus  may  occur,  into  the  axilla,  forwards 
under  the  pectoral  muscles,  or  backwards.  This  latter  species  is  extremely 
rare;  a dislocation  upwards  could  not  occur  without  fracture  of  the  acromion, 
and  therefore  cannot  be  considered  among  simple  dislocations.  A primary  dis- 
location, either  directly  backwards  or  directly  forwards,  is  not  likely  to  hap- 
pen, as  the  strong  attachments  of  the  teres  minor,  supra  and  infra-spinati  mus- 
cles to  the  greater  tubercle  of  the  humerus,  and  that  of  the  sub-scapular  to  the 
lesser  tubercles,  respectively  offer  powerful  resistance  in'  either  of  these  direc- 
tions. It  is  plain  then  from  the  constructions  of  this  joint,  that  a dislocation 
downwards,  where  the  head  of  the  bone  rests  on  the  sternal  costa  of  the  scapula, 
between  the  subscapularis  and  long  head  of  the  triceps,  is  the  most  likely  to 
occur ; for  the  lower  part  of  the  capsular  ligament  being  unsupported  by  mus- 
cles, is  most  weak;  and  the  action  of  the  levator  muscles  of  the  shoulder,  by 
rotating  the  head  of  the  humerus  from  above  down,  will  bring  the  head  of  the 
bone  near  the  inferior  edge  of  the  glenoid  cavity  and  thus  place  it  in  a situa- 
tion most  favorable  for  displacement,  when  violence  is  applied  to  the  extended 
arm.  There  is  but  one  circumstance  in  the  construction  of  the  joint  which  has 
a tendency  to  counteract  the  accident,  which  is,  that  the  glenoid  cavity  is  of 
greater  extent  from  above  down  than  across. 

DISLOCATION  DOWNWARDS. 

When  the  humerus  is  dislocated  downwards,  the  head  of  the  bone  is  found 
resting  on  the  sternal  costaof  the  scapula,  between  the  long  head  of  the  triceps 
and  sub-scapularis.  The  lower  portion  of  the  capsular  ligament  is  ruptured,  and 
sometimes  the  tendon  of  the  sub-scapularis ; the  tendons  of  the  supra  and  infra- 
spinati  muscles  and  of  the  teres  minor  are  also  sometimes  lacerated.  The 
anatomy  of  the  sound  joint  would  lead  us  to  conclude  that  these  latter  muscles 
should  be  injured  much  more  frequently  than  the  former,  but  dissections  of 
dislocated  shoulder -joints  have  proved  the  contrary.  Some  of  the  fibres  of 
the  deltoid,  pectoralis  major,  and  coraco-brachialis  are  occasionally  torn  ; the 
long  tendon  of  the  biceps  usually  remains  unbroken.  Independent  of  external 
violence,  the  elevating  muscles  of  the  humerus,  and  of  the  whole  arm,  (if  the 
elbow  jointbe  fixed,)  with  the  pectoralis  major,  latissimus  dorsi  and  teres  major 
may,  under  certain  circumstances,  effect  this  displacement  of  the  bone.  The 
deltoid  and  supra-spinatus  muscles  are  those  which  most  powerfully  resist 
reduction. 

DISLOCATION  FORWARDS. 

When  the  head  of  the  humerus  is  thrown  forwards,  it  lies  on  the  inner  side 
of  the  neck  of  the  scapula,  between  it  and  the  second  and  third  ribs.  The 
internal  portion  of  the  capsular  ligament  and  the  tendon  of  the  subscapularis 
39 


306 


THE  DUBLIN  DISSECTOR, 


are  ruptured  ; though  examples  have  occured  in  which  the  luxation  has  taken 
place  without  laceration  of  the  tendons  of  any  of  the  muscles  surrounding  the 
joint.  As  has  been  already  mentioned,  the  action  of  the  muscles,  attached  to 
the  greater  tubercle  of  the  humerus,  counteracts  forces  tending  to  produce  this 
species  of  displacement. 

DISLOCATION  BACKWARDS. 

Dislocation  backwards  under  the  spine  of  scapula  is  extremely  rare  ; it 
does  not  present  any  thing  worthy  of  particular  remark.  In  a ease  mentioned 
by  Delpech,  the  head  of  the  bone  lay  in  immediate  contact  with  the  scapula, 
under  the  infra-spinatus  muscle. 

of  dislocation  of  the  elbow-joint. 

A dislocation  of  the  elbow-joint  most  frequently  takes  place  by  a luxation 
backwards  of  both  radius  and  ulna.  The  accident  is  sometimes  complicated 
with  a fracture  of  the  coronoid  process  of  the  ulna.  It  is  facilitated  by  the 
relation  of  the  articulating  surfaces  in  the  semi-flexed  position  of  the  arm  ; 
when,  if  external  violence  be  applied,  the  coronoid  process  slips  behind  the 
internal  articular  pulley  of  the  humerus  and  is  lodged  in  the  sigmoid  fossa, 
while  the  humerus  is  thrown  forwards  on  the  radius  and  ulna.  The  external, 
internal,  and  sometimes  the  annular  ligament  of  the  radius  are  ruptured, 
though  the  accident  may  occur  .without  injury  to  any  of  these  parts;  occa- 
sionally the  biceps  and  brachialis  internus  suffer  from  the  violent  projection 
of  the  humerus.  The  brachial  artery  also  has  been  ruptured  in  this  manner. 
The  flexor  muscles  of  the  arm,  by  keeping  it  bent,  and  the  triceps  by  its  con- 
traction, are  the  muscles  which  oppose  reduction.  The  internal  condyle  of 
the  humerus  and  the  olecranon  present  two  prominent  points,  which  are  of 
great  importance  in  assisting  us  to  detect  injuries  about  the  elbow -joint.  In 
the  extended  position  of  the  arm  they  are  nearly  on  the  same  line,  and  anv 
displacement  of  the  bones  will  cause  a corresponding  displacement  of  these 
two  prominences. 

The  form  of  the  bones,  the  strength  of  the  lateral  ligaments,  and  the  nume- 
rous muscles  surrounding  the  joint,  prevent  a complete  lateral  luxation  of  both 
ulna  and  radius,  while  a luxation  forwards  cannot  occur  without  fracture  of 
the  olecranon. 

of  dislocations  of  the  humeral  extremity  of  the  radius. 

The  radius  may  be  dislocated  at  the  humeral  extremity,  either  backwards 
or  forwards.  When  the  radius  is  driven  through  the  back  part  of  the  capsu- 
lar ligament  it  is  found  to  rest  above  the  external  condyle  of  the  humerus, 
supported  by  the  brachial  fascia.  The  accessory  and  annular  ligaments  are 
torn,  and  sometimes  the  interosseous  ligament  suffers  at  its  superior  part. 

In  dislocation  forwards  of  the  radius,  the  head  of  the  bone  rests  above  the 
external  condyle  of  the  os  humeri.  The  accessory  and  annular  ligaments,  with 
a portion  of  the  interosseous  ligament,  are  ruptured  in  this  luxation  as  in  the 
former.  The  biceps  muscle  becomes  shorter  by  contraction,  and  thus  may 
resist,  though'  not  in  any  great  degree,  reduction. 


OR  MANUAL  OF  ANATOMY 


507 


OF  DISLOCATION  OF  THE  HUMERAL  EXTREMITY  OF  THE  ULNA. 

The  ulna  may  be  dislocated  backwards  on  the  os  humeri  without  being 
accompanied  by  the  radius.  The  coronoid  process  is  forced  over  the  pulley 
of  the  humerus  into  the  sigmoid  fossa,  and  the  olecranon  forms  a prominent 
projection  at  the  back  part.  The  annular  and  accessory  ligaments  are  ruptured, 
and  sometimes  a small  portion  of  the  interosseous.  The  action  of  the  triceps 
will  contribute  to  keep  the  bone  in  this  position,  while  on  the  contrary,  the 
brachialis  internus  assists  in  the  reduction. 

OF  DISLOCATIONS  OF  THE  JOINT  OF  THE  WRIST 

The  wrist  joint  may  be  dislocated  either  by  the  radius  and  ulna  being  both 
thrown  forwards,  or  both  backwards.  Lateral  dislocations  are  always  partial. 
As  these  displacements  always  occur  by  falls  on  the  ground,  or  other  violence, 
by  which  the  hand  is  forcibly  bent  on  the  bones  of  the  fore-arm,  extensive 
laceration  of  the  capsular,  anterior,  or  posterior  ligaments,  must  accompany 
them.  The  tendons  also  of  the  flexor  and  extensor  muscles  are  more  or  less 
displaced,  and' some  of  them  may  be  ruptured.  The  form  of  the  arch  of  the 
first  range  of  metacarpal  bones  favors  the  dislocation  backwards,  since  from 
theirgreater  convexity  in  this  direction,  they  do  not  afford  as  much  support  to 
the  bones  of  the  fore-arm. 

OF  DISLOCATION  OF  THE  CARPAL  EX^IEMITY  OF  THE  RADIUS.  ' 

The  carpal,  extremity  of  the  radius  maybe  dislocated  either  forwards  or 
backwards ; the  first  of  these  accidents  is  mucli  the  more  frequent.  The  bone 
is  thrown  forwards  on  the  scaphoid  and  os  trapezium.  The  capsular  and 
anterior  ligaments  alone  are  ruptured.  If  the  head  of  the  radius  be  thrown 
back  from  its  articulating  surfaces,  the  back  part  of  the  capsule,  the  posterior, 
and  sometimes  the  external  lateral  ligament  are  ruptured.  The  bone  projects 
under  the  skin  at  the  back  of  the  wrist. 

Separate  dislocation  of  the  carpal  extremity  of  the  ulna  takes  place  either 
forwards  or  backwards.  The  only  circumstance  worthy  of  notice  is  the 
difficulty  of  keeping  the  bone  in  its  place,  in  consequence  of  the  rupture  of  the 
sacciform  ligament. 

The  close  connection  of  the  bones  of  the  carpus,  and  the  numerous  ligaments 
spread  in  all  directions  over  the  back  and  front  of  the  hand,  present  powerful 
obstacles  to  complete  dislocations  of  any  of  these  bones  : in  fact,  surgeons  of 
the  greatest  experience  have  never  met  with  such  an  accident.  The  only  part 
of  the  articulation  at  which  it  is  likely  to  occur,  is  where  the  head  of  the  os 
magnum  is  received  into  the  depression  of  the  semi-lunar  and  scaphoid  bones, 
because  here  the  quantity  of  motion  is  greatest;  however  it  is  almost  invaria- 
bly incomplete. 

OF  DISLOCATIONS  OF  THE  THUMB. 

The  first  metacarpal  bone  may  be  dislocated  from  its  articulation  with  the 
trapezium  forwards  or  backwards;  in  the  backward  luxation  the  carpal 


308 


THE  DUBLIN  DISSECTOR, 


extremity  of  the  bone  is  driven  through  the  posterior  part  of  the  capsulai 
ligament.  It  does  not  appear  necessary  that  the  lateral  ligaments  should  be 
ruptured.  The  flexor  ossis  metacarpi,  and  flexor  brevis  and  longus,  with  the 
abductor,  offer  great  resistance  to  reduction  when  delayed  for  any  time. 

In  dislocation  forwards  the  metacarpal  bone  is  thrown  between  the  trape 
zium  and  the  root  of  the  second  metacarpal  bone.  The  thumb  is  bent  back, 
and  cannot  be  flexed.  The  external  lateral  ligament  is  in  this  case  more 
likely  to  be  torn  than  in  the  former.  The  extensors  of  the  thumb  are  the 
muscles  which  offer  resistance  to  reduction  of  this  dislocation. 

OF  DISLOCATION  OF  THE  FIRST  PHALANX  OF  THE  THUMB. 

The  first  phalanx  of  the  thumb  is  frequently  dislocated  backwards,  from 
the  head  of  the  metacarpal  bone.  The  lateral  ligaments  remain  uninjured. 
This  dislocation  is  interesting  from  the  great  difficulty  of  reducing  it  when 
neglected  even  for  a short  time.  The  phalanges  of  the  other  fingers  may  be 
dislocated  either  backwards  or  forwards,  but  present  nothing  worthy  of  atten- 
tion. 


OF  DISLOCATION  OF  THE  HIP  JOINT. 

The  joint  of  the  hip  may  be  dislocated  in  four  ways,  backwards  and  up 
wards  on  the  dorsum  of  the  ilium,  backwards  on  the  ischiatic  notch,  forwards 
and  upwards  on  the  pubes,  and  forwards  and  downwards  on  the  foramen 
obturatorium. 

The  hip  joint  is  not  at  all  so  liable  to  dislocation  as  that  of  the  shoulder;  for 
this  several  reasons  may  be  assigned.  In  the  first  place,  its  motions  are  much 
more  limited  both  in  number  and  extent.  The  glenoid  cavity  affords  little 
mechanical  security,  while  the  cotyloid  on  the  contrary  permits  the  head  of 
the  femur  to  sink  into  it.  The  oblique  direction  also  of  the  head  of  the  thigh 
bone  presents  an  additional  obstacle  ; the  capsular  ligament  of  this  joint  is 
much  stronger  than  that  of  the  shoulder,  and  it  is  further  protected  by  strong 
accessory  fibres  on  the  outer  and  upper  part,  which  descend  from  the  inferior 
anterior' spine  of  the  ilium,  and  by  some  on  the  inner  side  from  the  superior 
part  of  the  foramen  ovale.  The  articulation  of. the  hip  is  also  more  closely 
invested  by  muscles  ; above  we  have  the  gluteus  minimus  and  tendon  of  the 
psoas  and  iliacus  muscles.  In  front  the  rectus  ; on  the  inside,  the  pectinaiis 
and  obturator  externus ; and  behind,  the  quadratus  femoris,  gemini,  pyriformis, 
and  obturator  internus.  The  situation  of  the  trochanter  major  is  a point  of 
great  importance  in  discriminating  accident  about  the  hip  joint,  and  its  rela- 
tion to  some  other  prominent  points  should  be  well  kept  in  mind.  In  the 
erect  position  of  the  body,  the  superior  part  of  the  trochanter  major  is  nearly 
on  the  same  level  with  the  body  of  the  pubes.  The  distance  between  the 
anterior  superior  spine  of  the  ilium  and  the  trochanter  major  is  less  than  from 
this  projection  to  the  os  pubis,  or  from  the  os  pubis  to  the  anterior  superior 
spine;  and  lines  connecting  these  three  points  will  form  nearly  a right  angled 
triangle,  of  which  the  longest  side  is  the  line  connecting  the  superior  spine  to 
the  pubis  ; and  the  shortest,  that  which  joins  the  spine  teethe  trochanter.  In 
dislocation  upwards  or  backwards  the  trochanter  is  brought  nearer  the  superior 


OR  3IANUAL  OF  ANATOMY, 


309 


anterior  spine  of  tne  ileum.  In  the  backward  luxation  it  is  removed  from 
the  body  of  the  pubis,  and  is  not  as  prominent  as  in  the  natural  state.  In  the 
dislocation  into  the  obturator  foramen,  the  distance  between  the  trochanter 
major  and  the  body  of  the  pubis  is  lessened ; while  that  between  this  process 
and  the  anterior  superior  spine  is  greater  than  usual. 

In  dislocation  upwards  and  backwards  the  head  of  the  bone  rests  on  the 
dorsum  of  the  ileum.  The  upper  part  of  the  capsular  ligament  is  ruptured  ; 
and  the  external  accessory  and  round  ligaments  are  torn.  In  rotation  inwards 
the  head  of  the  femur  is  pressed  against  the  back  part  of  the  capsular  ligament, 
and  if  the  rotation  be  carried  far,  a considerable  portion  of  the  bone  is  outside 
the  cotyloid  cavity : hence  the  species  of  dislocation  now  described  is  most 
likely  to  occur  when  rotation  inwards  is  accompanied  by  external  violence. 

When  dislocation  has  occured  the  three  glutei  muscles  are  those  principally 
concerned  in  keeping  the  head  of  the  bone  fixed  on  the  dorsum  of  the  ileum ; 
but  when  the  head  of  the  bone  is  sufficiently  raised  to  pass  over  the  edge  of 
the  acetabulum,  the  psoas  and  iliacus  with  the  obturator  externusand  pectinalis, 
will  assist  to  bring  it  into  the  proper  situation.  Although  in  common  cases 
of  dislocation  no  other  injury  is  done  to  the  joint  than  what  has  been  already 
described,  the  dissection  of  a luxation  upwards  and  backwards  has  been 
published,  in  which  the  gemini,  pyriformis,  obturators,  and  quadratus  femoris, 
were  completely  torn  across,  with  laceration  of  some  fibres  of  the  pectinalis. 

In  the  dislocation  backwards  on  the  ischiatic  notch  the  head  of  the  bone  rests 
on  the  pyriformis  muscle.  This  dislocation  also  is  most  likely  to  happen  when 
the  thigh  is  rotated  inwards  and  bent  towards  the  abdomen.  The  pyriformis, 
gemini,  and  obturator  internus  muscles  keep  the  bone  in  the  dislocated  posi- 
tion; while  the  psoas,  iliacus  and  obturator  externus  favor  reduction.  When 
the  femur  is  dislocated  forwards  on  the  obturator  foramen,  the  capsular  liga- 
ment and  the  internal  accessory  fibres  are  lacerated.  The  ligamentum  teres 
is  not  always  ruptured.  The  pectinseus  and  adductor  brevis  (if  not  lacerated, 
which  often  takes  place)  will  keep  the  bone  in  its  new  situation  ; while  the 
glutei  and  all  the  muscles  arising  behind  the  acetabulum  will  contribute  to 
bring  it  back  to  its  proper  place.  In  dislocation  upwards  and  forwards  the 
head  of  the  bone  rests  on  the  ramus  of  the  pubes  under  Poupart’s  ligament, 
where  it  may  be  plainly  felt.  The  gemini,  obturator  internus,  and  pyriformis 
if  not  ruptured)  would  favor  reduction.  A calculation  has  been  made,  that 
out  of  twenty  dislocations  of  the  hip  joint,  twelve  will  take  place  on  the  dor- 
sum ilii ; five  on  the  ischiatic  notch;  two  on  the  foramen  ovale;  and  one  on 
the  pubes. 

OF  DISLOCATION  OF  THE  JOINT  OF  THE  KNEE. 

Dislocation  of  the  patella  may  take  place  either  upwards,  inwards,  or  out- 
wards: the  latter  is  the  more  frequent  form:  a dislocation  upwards  could 
not  occur  without  rupture  of  the  inferior  ligament  of  the  patella,  which  is  so 
strong  that  frequently  in  violent  action  of  the  extensor  muscles,  the  patella 
itself  snaps  across  before  this  ligament  gives  way.  When  the  knee  is  much 
bent  dislocation  in  either  direction  cannot  take  place.  The  extent  of  the 
articulating  surfaces  of  the  femur,  and  the  force  with  which  the  patella  is 
pressed  in  between  the  condyles  prevents  such  an  accident.  The  position 


310 


THE  DUBLIN  DISSECTOR, 


most  favorable  to  this  luxation  is  where  the  knee  is  slightly  bent  and  inclined 
inwards.  When  complete  luxation  of  the  patella  outwards  has  taken  place, 
the  patella  rests  over  the  external  condyle  of  the  femur,  in  which  place  it  is 
fixed  by  the  rectus,  crureus,  and  vasti  muscles:  hence,  the  necessity  for 
bending  the  thigh  on  the  pelvis,  in  order  to  relax  these  muscles  as  much  as 
possible.  The  extent  of  the  synovial  membrane  permits  this  displacement  to 
occur  without  any  rupture.  Dislocation  of  the  patella  inwards  is  so  similar 
in  its  nature  to  the  outward  luxation  that  it  does  not  require  any  notice. 

The  tibia  may  be  dislocated  from  the  femur,  backwards,  forwards,  or  to 
either  side.  Of  these  the  only  one  likely  to  be  complete  is  the  backward  : 
lateral  luxations  are  always  partial.  There  is  no  joint  in  the  body  so  well 
supported  by  ligaments  as  that  of  the  knee ; on  the  sides  we  have  the  lateral 
ligaments ; in  front  the  ligament  of  the  patella  and  the  tendinous  insertion  of 
the  extensor  muscles  ; behind  the  posterior  ligament  of  Winslow;  and  more 
particularly  the  strong  crucial  ligaments.  Additional  ligamentous  bands  are 
also  occasionally  seen.  When  the  tibia  is  completely  dislocated  backwards, 
into  the  ham,  the  ligamentous  attachments  of  the  patella  either  above  or  below 
must  give  way.  The  crucial  and  posterior  ligaments  are  also  torn.  The 
ffexor  muscles  of  the  leg,  which  are  attached  to  the  tibia,  will  contribute  to 
keep  the  bone  in  the  luxated  position.  Complete  forward  dislocations  of  the 
tibia  have  occurred,  but  they  are  very  rare.  In  such  case;  all  the  ligaments 
of  the  joint  must  give  way,  and  the  heads  of  the  gastrocncinii  and  poplitcu3 
muscles  would  also  probably  suffer. 

OF  DISLOCATION  OF  THE  UPPER  HEAD  OF  THE  FIBULA. 

Luxation  of  the  upper  head  of  the  fibula  is  usually  the  consequence  of 
disease  ; for  the  application  of  a force  sufficient  to  dislocate  the  bone  is  much 
more  likely  to  break  it.  The  action  of  the  biceps  flexor,  the  only  muscle  in- 
serted into  the  fibula,  could  not  alone  produce  this  accident.  When  the  head 
of  the  fibula  is  thrown  back,  the  anterior  ligament  and  the  accessory  fibres 
from  the  tendon  of  the  biceps,  with  the  synovial  capsule,  are  ruptured.  Boyer 
mentions  a case  in  which  the  whole  fibula  was  driven  directly  upwards  in 
consequence  of  a dislocation  outwards  of  the  ankle. 

of  dislocation  of  the  tarsal  extremity  of  the  tibia. 

The  tibia  may  be  dislocated  at  its  tarsal  extremity,  backwards,  forwards, 
or  to  either  side.  Luxation  inwards  is  the  most  common.  These  accidents 
can  be  produced  by  external  violence  alone.  W hen  the  tibia  is  luxated  in- 
wards it  is  found  resting  on  the  inner  side  of  the  astragalus  and  os  calcis.  The 
fibula  is  broken  usually  at  its  lower  third,  and  the  broken  end  of  this  bone  is 
situated  on  the  astragalus.  The  synovial  membrane  is  ruptured  with  lacera- 
tion of  the  deltoid  and  anterior  ligaments  of  the  tibia,  and  ot  the  posterior 
transverse  band  from  the  tibia  to  the  fibula.  After  the  accident  has  taken 
place,  contraction  of  the  gastrocnemii,  solei,  and  peronaei  muscles,  by  rotating 
the  foot  out  and  drawing  it  upwards,  will  offer  resistance  to  reduction.  If 
the  tibia  be  dislocated  outwards,  the  malleolus  internus  must  be  brokep  off; 
the  deltoid  ligament  is  not  ruptured ; but  if  the  fibula  be  not  broken,  the 


OR  MANUAL  OF  ANATOMY. 


311 


external  lateral,  anterior  and  posterior  ligaments  of  this  bone  are  lacerated.  In 
the  forward  dislocation,  the  fibula  and  usually  the  malleolus  internus  are 
broken.  The  tibia  rests  on  the  os  naviculare  and  internal  cuneiform  bone.  The 
posterior  part  of  the  deltoid  ligament,  and  the  transverse  band  from  the  tibia  to 
the  fibula  are  ruptured.  Dislocation  forwards  is  an  accident  of  rare  occurrence. 
It  cannot  happen  when  the  foot  is  flexed  on  the  tibia,  for  then  the  tibia  sinks 
down  on  the  back  part  of  the  astragalus,  and  nothing  but  considerable  force 
could  raise  it  over  the  upper  portion  of  the  bone,  which,  in  this  position, 
extends  like  a bridge  before  it. 

Luxation  backwards  is  even  still  more  rare.  Were  such  an  accident  to 
take  place  all  the  tibial  ligaments  would  be  broken,  and  the  fibula  most  pro- 
bably fractured. 

The  astragalus,  the  os  cuneiform  internum,  and  the  range  of  tarsal  bones 
articulated  with  the  os  calcis  and  astragalus,  are  sometimes  dislocated  simply, 
but  the  accident  is  of  very  rare  occurrence.  Dislocations  of  the  phalanges  of 
the  toes  are  similar  to  those  already  described  as  taking  place  in  the  fingers, 
and  do  not  deserve  particular  notice. 

DIRECTIONS  FOR  MAKING  DRIED  PREPARATIONS  OF  ARTERIES. 

Although  in  every  anatomical  school  competent  persons  are  retained  for 
the  purpose  of  injecting  arteries  and  veins  ; still  the  student  may  wish  to  do 
it  for  himself,  or  he  may  be  placed  in  such  situations  that  he  cannot  command, 
any  kind  of  assistance ; to  him,  more  particularly,  the  few  remarks  which  we 
purpose  making  on  the  method  of  injecting  and  of  preserving  arterial  pre- 
parations, may  be  considered  applicable. 

Injections  are  of  two  kinds,  coarse  and  fine;  there  are  many  descriptions 
of  coarse  injections ; with  the  fine  we  have  nothing  to  do,  as  it  is  used  by  ana- 
tomists only  for  the  purpose  of  imitating  the  natural  vascularity  which  mem- 
branes and  other  structures  lose  after  death.  Coarse  injections  may  be  em- 
ployed either  hot  or  cold,  formerly  the  hot  injection  was  the  only  one  used, 
but  now  the  cold  one  is  very  frequently  employed.  As  much  of  the  success 
of  the  injection  depends  on  the  state  of  the  subject,  great  care  should  be  ob- 
served in  the  choice;  if  possible  a young  and  thin  one  should  always  be  em- 
ployed, as  the  arteries  in  old  subjects  are  so  often  ossified  and  inelastic,  that 
we  can  never  be  certain  that  they  will  not  burst  from  the  force  employed,  and 
extravasate  the  injection  between  the  muscles  and  into  the  different  cavities; 
another  objection  to  the  use  of  old  subjects  is,  that  the  constant  oozing  of  oily 
matter  from  preparations  made  of  them  renders  them  filthy,  and  almost  use- 
less, particularly  in  warm  weather  ; however,  some  old  subjects  may  be  filled 
with  the  cold  (or  paint)  injection,  if  care  be  taken  not  to  use  too  much  force. 
When  the  student  has  made  up  his  mind  to  employ  the  hot  injection,  it  may 
be  useful  to  him  to  follow  a few  rules.  In  the  first  place  the  pipe  should  be 
tied  so  firmly  in  the  opening  into  the  vessel,  that  there  will  be  no  possibility 
of  its  slipping  out ; secondly,  the  nozzle  of  the  syringe  should  always  be  intro- 
duced into  the  pipe,  for  the  purpose  of  exhausting  the  artery  of  air  or  coagu- 
lated blood  ; this  being  done  the  stopcock  should  be  immediately  turned  ; and 
lastly,  particular  care  should  be  taken  that  the  syringe,  pipe,  and  stopcock 
are  free  and  in  good  order. 


312 


THE  DUBLIN  DISSECTOR, 


% 

To  inject  with  the  hot  injection,  it  is  necessary  that  tne  subject  should  be 
thoroughly  heated  ; this  is  best  done  by  opening  the  cavities  of  the  thorax  and 
abdomen,  and  filling  them  with  waterof  a temperature  that,  the  hand  can  bear; 
the  body  at  the  same  time  should  be  immersed  in  water  of  the  same  tempera- 
ture, takingcare  toexclude  atmospheric  air  as  much  as  possible.  The  process 
of  heating  should  be  carried  on  until  the  subject  has  acquired  a temperature 
resembling  the  natural  heat  of  the  living  body.  While  this  is  going  on,  the 
injection  should  be  particularly  attended-  to,  as  the  materials  are  very  inflam- 
mable, and  if  care  be  not  taken,  or  much  heat  be  employed,  there  will  be  dan- 
ger of  burning  the  chimney  or  house ; beat  slowly  applied  will  melt  the 
injection  without  any  admixtureof  air,  or  endangering  the  loss  of  color,  which 
strong  heat  would  certainly  effect.  When  the  subject  and  injection  are  suffi- 
ciently heated,  the  injection  should  be  sucked  up  twice  or  thrice,  so  as  to  mix 
it  well  with  the  coloring  matter,  which  always  falls  to  the  bottom  ; before  the 
syringe  is  introduced  into  the  pipe,  it  should  beheld  up  and  the  piston  pressed 
till  the  injection  appears,  by  which  any  air  that  may  be  in  the  syringe  will  be 
permitted  to  escape ; taking  the  wings  of  the  pipe  in  the  left  hand,  the  syringe 
is  to  be  introduced,  and  the  piston  is  to  be  pushed  down  slowly  and  gradually 
with  the  right  hand,  until  the  syringe  is  emptied  ; this  action  is  to  be  repeated, 
till  we  feel  resistance  made  to  the  further  passage  of  the  fluid  in  the  artedes; 
if  after  this  resistance  is  felt,  any  further  force  be  used,  there  will  be  great 
danger  of  rupturing  the  arteries  and  producing  extravasation.  As  soon  as  we 
are  satisfied  that  the  body  is  injected,  it  should  be  put  in  cold  water,  where  it 
should  remain  for  a few  hours.  Either  of  the  following  hot  injections  may  be 
used  : 

Wax  gxvi. 

Resin  3 viii. 

Turpentine  Varnish  Sjviii. 

Chinese  Vermilion  §i. 

This  makes  a very  handsome  injection,  but  it  is  liable  to  the  inconvenience 
of  melting  in  warm  weather,  and  in  this  way  producing  a flattened  appearance 
in  the  blood  vessels.  A much  cheaper  and  better  injection  for  common  pur- 
poses than  the  above  has  been  employed;  it  is  made  of 

Tallow  2lbs. 

Magnesia  Usta  ~ss. 

Chinese  Vermilion  31. 

This  possesses  all  the  advantages  of  the  wax  injection  without  any  of  its 
inconveniences;  it  is  as  transparent  nearly  as  the  wax,  never  melts  in  the 
hottest  weather,  and  is  not  disposed  to  crack  ; if  this  injection  be  used  very 
hot,  an  extremity  may  be  injected  without  having  been  previously  heated  : 
but  this  should  never  be  done  except  by  persons  skilled  in  the  art  of  in- 
jecting. 

If  we  wish  to  trace  the  minute  branches  of  arteries,  and  examine  their 
various  communications,  there  are  no  injections  better  adapted  for  common 
purposes  than  that  of  tallow  and  red  lead  well  mixed  and  heated,  or  the  cold 
paint  injection;  if  the  latter  be  well  thrown  in,  the  minutest  arteries,  for 
instance  the  ciliary,  will  be  injected  ; it  is  made  of 

White  lead,  well  grouud,  Gibs, 

Turpentine  Varnish  §xii. 

Drying  Oil  gvi. 


OR  manual  of  anatomy. 


SIS 


The  lead  is  intimately  mixed  with  the  varnish,  and  then  the  oil  is  to  be  added; 
they  are  all  to  be  well  mixed  up  together,  to  the  consistence  of  cream,  and  in 
this  State  it  is  to  be  thrown  into  the  arteries ; the  same  precautions,  with 
regard  to  the  exclusion  of  air  from  the  syringe,  and  the  degree  of  force  to  be 
used,  are  to  be  observed  in  this  as  well  as  in  the  hot  injection.  Arteries  are 
always  injected  from  the  aorta  or  some  other  large  trunk;  while  veins  are 
injected  differently ; in  making  preparations  of  veins,  it  is  necessary  to  inject 
them  from  the  extreme  branches  towards  the  trunks,  on  account  of  the  direc- 
tion of  the  valves  ; for  instance,  the  veins  of  the  arm  are  to  be  injected  from  a 
small  branch  on  the  back  of  the  hand,  and  those  of  the  leg  and  thigh  from  some 
branch  on  the  dorsum  of  the  foot.  Previously  to  the  injection  being  made,  it 
is  necessary  that  the  veins  should  be  well  washed  out  with  warm  water,  to 
remove  the  coagula  of  blood  which  they  generally  contain ; if  the  veins  of  the 
arm  are  to  be  injected,  an  opening  should  be  made  in  the  subclavian  vein,  to 
allow  the  warm  water  and  coagula  to  pass  out : when  this  has  happened,  a 
ligature  previously  applied  is  to  be  firmly  tied  round  the  vessel,  which  will 
prevent  the  injection  from  flowing  out;  the  same  rule  applies  to  the  injection 
of  veins  in  the  lower  extremity.  The  veins  of  the  head  and  neck  are  gene- 
rally injected  from  the  superior  longitudinal  sinus  : it  is  scarcely  necessary  to 
mention  that  veins  are  filled  with  blue  fluid,  and  the  arteries  with  white  or  red  ; 
for  the  blue  injection  smalt  blue  is  usually  employed.  To  inject  the  arteries 
a transverse  cut  is  to  be  made  in  the  aorta,  as  close  to  its  origin  from  the  heart 
as  possible.  Care  must  be  taken  that  the  extremity  of  the  pipe  does  not  pro- 
ject so  far  as  to  pass  into  the  innominata,  or  one  of  the  vessels  arising  from 
the  left  side  of  the  arch,  as  this  would  give  only  a partial  injection.  The 
nozzle  of  the  pipe  being  carefully  inserted  into  the  opening  of  the  vessel,  two 
pieces  of  twine  are  to  be  introduced  under  the  vessel ; one  of  these  is  to  be 
firmly  tied  round  the  artery,  this  will  embrace  the  nozzle  of  the  pipe,  its  loose 
extremities,  when  the  knot  is  firmly  tied,  are  to  be  fixed  to  the  wings  of  the 
pipe  in  order  to  prevent  any  chance  of  its  slipping  out  of  the  vessel.  The 
other  ligature  is  to  remain  loose  under  the  vessel,  beyond  the  nozzle  of  the 
pipe  about  one  inch.  After  injection  is  thrown  in,  this  ligature  is  also  to  be 
firmly  tied  round  the  vessel,  leaving  the  pipe  clear  ; the  use  of  it  is,  that  the 
injection  may  not  return  back  when  the  pipe  is  removed  from  the  aorta.  This 
precaution  is  more  particularly  necessary  when  the  paint  injection  is  used. 
In  inserting  a pipe  into  a small  artery  or  vein,  some  difficulty  may  arise  in 
the  introduction  from  the  pipe  being  larger  than  the  calibre  of  the  vessel ; in 
this  case  the  point  of  a scissors  should  be  introduced  into  the  vessel,  and 
gradual  dilatation  produced  by  slowly  opening  its  blades.  When  the  injec- 
tion has  remained  sufficiently  long  to  set  well  in  the  vessels,  dissection  may 
be  commenced,  and  here  it  is  a rule  which  should  be  invariably  followed,  that 
the  dissection  be  completed  in  as  short  a time  as  is  consistent  with  a proper 
display  of  the  vessels,  for  many  preparations  are  lost  in  consequence  ot  the 
part  first  dissected  becoming  spoiled  before  the  remainder  is  prepared  for 
drying.  Particular  care  should  be  taken  to  remove  all  the  cellular  substance 
from  the  coats  of  the  vessels  ; if  this  be  not  done,  the  preparation  will  always 
have  a dirty  appearance.  The  fatty  matter  is  likewise  to  be  removed,  but  no 
muscle  is  to  be  taken  away  or  pushed  from  its  situation  unless  perfectly 
unavoidable.  The  student  should  always  remember  that  the  utility  of  a dried 
40 


314 


THE  DUBLIN  DISSECTOR,  &C. 


preparation  consists  in  its  preserving,  as  far  as  possible,  the  natural  relation  of 
parts ; on  this  account,  the  use  of  pieces  of  stick  or  other  substances  to  separate  A 
the  muscles  and  exhibit  the  course  of  the  vessels,  unless  absolutely  necessary, 
is  to  be  condemned.  One  side  of  the  subject  ought  to  be  appropriated  to  the 
exhibition  of  the  superficial  vessels,  the  other  may  be  used  for  the  deep  seated. 
When  the  dissection  is  completed,  the  extremity,  or  whatever  portion  of  the 
body  it  may  be,  should  be  hung  up  in  a dry  and  airy  situation  (but  not  exposed 
to  the  sun)  until  the  muscles  acquire  firmness,  and  no  exudation  appears  on 
their  surface.  The  preparation  now  fit  for  us’e,  is  to  be  brushed  over  with 
copal  or  mastich  varnish,  which  makes  the  vessels  more  distinct,  and  materially 
assists  in  its  future  preservation. 


THE  END. 


( 


